Webster  Family  Library  of  Veterinary  ^yledicine 
Cummings  School  of  Veterinary  Medicine  at 
Tufts  University 
200  Westboro  Road 
North  Grafton.  MA  01536 


VETERINARY  MEDICINE  SERIES 

No.  17 
Edited  by  D.  M.  Campbell 


FISTULA  OF  THE  WITHERS 
AND  POLL-EVIL 


BY 


Major  L.  A.  MERILLAT,  Sr.,  V.  C,  N.  A., 

Editor,  Department  of  Surgery, 

.American   Journal   of  Veterinary   Medicine 


Published  by 

Americ:in  Veterinary  Publishing  Co., 

Chicago 


Copyright,  1917,  by 

American  Veterinary  Publishing  Co. 

Chicago 


CONTENTS 

FISTULA  OF  THE  WITHERS  Page 

Introduction    7 

The  Withers  13 

Pathogenesis  37 

Symptoms    57 

Treatment   67 

POLL-EVIL 

The  Poll  105 

Pathogenesis 113 

Symptoms    121 

Treatment 127 


PREFACE 

There  are  several  reasons  why  a  manual  on 
this  disease  should  be  a  part  of  the  veterinary 
literature  of  the  day,  the  chief  one  being  that 
fistula  of  the  withers  is  a  very  prevalent  disease 
of  horses  and  thus  exacts  a  big  toll  from  the 
horse  industry.  Another  reason  for  bringing 
it  especially  to  the  attention  of  readers  of  vet- 
erinary literature  is  the  deplorable  fact  that 
its  treatment  has  never  been  standardized  in 
the  veterinary  profession.  Almost  all  long 
known  and  common  complaints  of  domestic 
animals  of  a  serious  character  are  handled  ac- 
cording to  definite  plans,  differing  only  in 
minor  details.  The  many  conferences  of  our 
teachers  of  surgery  in  association  work,  and 
the  interchange  of  ideas  made  possible  by  the 
splendid  periodicals  which  all  progressive  vet- 
erinarians now  read,  as  well  as  the  profusion 
of  all  kinds  of  literature  that  reaches  everyone, 
has  fortunately  created  a  standard  of  treat- 
ment for  nearly  all  of  the  more  important  ail- 
ments of  animals. 

Not  so,  however,  with  fistula  of  the  withers. 
Each  seems  to  have  his  own  plan  of  treatment 
and  few,  indeed,  claim  even  a  fair  degree  of 


6  PREFACE 

success.  Some  are  satisfied  with  caustics,  oth- 
ers with  lancing  and  irrigations,  others  with 
bacterins,  while  a  few  of  the  more  daring  pre- 
fer radical  surgery  that  removes  the  causative 
elements.  To  these  plans  might  also  be  added 
that  of  those  who  avoid  fistula  of  the  withers 
entirely,  because  of  the  discredit  meddlesome 
intervention  generally  brings  them. 

In  every  rural  community  of  the  Middle 
West  the  empiric  finds  a  fruitful  field  for  ex- 
ploitation in  the  many  chronic,  loathsome,  half- 
cured  fistula  of  the  withers  found  in  the  hands 
of  owners  willing  to  try  anything  after  having 
given  up  in  despair  the  various  treatments  that 
have  failed. 

If  this  book  will  do  no  more  than  to  inspire 
the  veterinary  practitioner  to  approach  this 
ailment  in  a  matter  of  fact  manner  and  to  han- 
dle it  according  to  the  common  laws  of  modern 
surgical  procedure;  and  if  it  will  discourage  a 
continuance  of  the  half-hearted  and  always  un- 
satisfactory methods  in  vogue,  the  effort  will 
not  have  been  lost.  The  Author. 

Camp  Mills,  N.  Y.,  December,  1917. 


INTRODUCTION 

The  disease  known  universally  among  Amer- 
ican veterinarians  as  fistula  of  the  withers  is 
described  at  much  greater  length  in  the  follow- 
ing pages  than  has  ever  been  done  before  in 
veterinary  literature.  Most  of  the  authors  of 
surgical  subjects  have  dismissed  this  affliction 
with  a  few  w^ords,  referring  to  it  only  incident- 
ally as  an  occasional  complication  of  harness 
galls  or  other  forms  of  trauma  about  the  crest 
of  the  neck  and  withers,  but  always  without 
dignifying  it  as  an  entity  w^orthy  of  special 
notice.  Its  frequent  origin  in  the  bursse  on  the 
thoracic  spines  of  the  region  and  its  develop- 
ment independent  of  any  apparent  injury  have 
only  recently  attracted  attention.  In  fact, 
there  are  many  who  still  entertain  the  opinion 
that  it  is  but  a  complication  of  a  contusion  in- 
flicted by  the  collar,  by  rolling  upon  hard 
ground,  by  striking  against  a  low  stable  beam, 
by  rubbing  against  branches  of  trees  while  at 
the  pasture,  or  by  bites  from  other  horses. 
Without  ever  having  been  able  to  attribute  any 
given  typical  fistula  of  the  withers  to  a  given 
traumatism,  the  theory  of  traumatic  origin 
has  been  indifferently  accepted  as  ample  expla- 


8  INTRODUCTION 

nation  of  its  cause.  Thus  years  have  been 
wasted  in  attacking  the  disease  from  without, 
giving  only  casual  attention  to  the  "interior" 
of  the  withers  where  it  actually  originates. 

We  do  not  insist  that  the  names  "fistulous 
withers"  or  "fistula  of  the  withers"  are  even 
good  appellatives  for  the  disease  we  are  about 
to  describe.  On  the  contrary,  a  name  less  spe- 
cially pathologic  in  its  meaning  would  seem 
more  appropriate,  since  fistula  is  but  a  phase  of 
the  entity  as  a  whole.  The  name,  inappro- 
priate as  it  is,  we  retain  because  among  our 
American  readers  it  has  been  consecrated  by  so 
many  years  of  usage  that  a  change  would  lead 
to  no  better  understanding  of  our  exposition  or 
argument.  We  retain  the  name,  therefore, 
with  the  full  knowledge  that  it  is  appropriate 
only  for  the  latter  stages  of  the  disease  and  that 
the  fistula  are  but  insignificant  parts  of  the 
total  pathogeny. 

Poll-evil,  which  we  argue  is  but  the  same 
condition  attacking  the  atlantal  bursa,  has,  on 
the  contrary,  been  more  extensively  described 
by  writers  throughout  the  history  of  modern 
veterinary  science,  and  although  it  had  been  re- 
ferred to  always  as  a  complication  of  a  trauma- 
tism in  the  earlier  days,  it  was  the  first  of  these 
two  diseases  to  be  recognized  as  a  bursitis.  It 
has  been  designated  as  inflammation  of  the 


INTRODUCTION  9 

bursa  of  the  ligamentum  nuchge  and  by  some 
writers  as  inflammation  of  the  ligament  itself. 
No  one  has  thus  far  been  able  to  prove  its  def- 
inite cause.  Like  fistula  of  the  withers,  ap- 
parently for  want  of  an  explanation  based  on 
demonstrable  facts,  it  has  always  been  attrib- 
uted to  bruisings  of  the  poll. 

While  we  do  not  entirely  eliminate  traimia- 
tism  as  the  cause  of  some  cases  of  poll-evil  and 
some  attacks  of  fistula  of  the  withers,  it  has 
been  our  experience  that  when  injuries  are  the 
cause,  the  wound  or  bruise  is  always  apparent 
and  the  disease  advances  into  the  depths  of  the 
region  by  gradual  stages  from  the  initial  focus 
deeper  and  deeper  until  the  interior  is  finally 
attacked  by  the  encroaching  pyogenic  process. 
In  ordinary  cases  of  both  of  these  afflictions, 
the  initial  focus  is  always  central,  far  down  in 
the  depths  of  the  body  where  external  violence 
can  have  but  little  influence.  From  this  cen- 
tral location  the  disease  as  gradually  advances 
in  the  outward  direction  in  the  ordinary  case, 
as  it  does  inward  in  the  exceptional  cases  due 
to  trauma.  We  have,  therefore,  no  choice 
than  that  of  describing  both  poll-evi]  and  fis- 
tula of  the  withers  as  having  two  distinct  caus- 
es, one  a  wound  or  bruise  at  the  very  surface, 
and  the  other,  and  commonest,  as  yet  imknown. 

The  prevalence  of  fistula  of  the  withers  and 


10  INTRODUCTION 

poll-evil  we  have  found  to  be  much  greater  in 
some  localities  than  others.  In  some  districts 
it  is  actually  an  equine  scourge,  while  in  others 
it  is  a  rare  occurrence.  In  southern  California, 
for  example,  veterinarians  seldom  if  ever  see 
a  typical  fistula  of  the  withers  or  poll-evil,  while 
in  central  Illinois  it  is  a  veritable  horse  plague. 
In  a  recent  conversation  with  an  old  horse 
breeder  in  the  latter  location  the  information 
was  elicited  that  fistula  was  once  as  rare  there 
as  in  California.  Asked  if  he  had  any  theory 
to  advance  as  to  the  cause  he  seemed  inclined  to 
attribute  most  cases  to  influenza,  and  colt  dis- 
temper, claiming  that  before  these  diseases  be- 
came prevalent  from  the  interchange  of  horses 
from  shipping  centers  there  were  no  cases  of 
fistula  of  the  withers.  The  rarity  of  shipping 
fever  (influenza)  in  California,  seems  to  add 
logic  to  these  observations. 

But  no  matter  what  the  cause  may  eventu- 
ally prove  to  be,  the  veterinary  practitioner  is 
today  confronted  with  a  serious  disease  of 
horses  that  he  must  endeavor  to  control  and 
handle  to  the  better  satisfaction  of  horse  breed- 
ers and  the  public.  To  fall  short  of  meeting 
this  requirement  is  one  more  adverse  reflection 
on  our  ability  to  meet  the  demands  of  our 
growing  live  stock  industry.  To  study,  to  ex- 
periment with,  to  strive  to  curb,  and  to  analyze 


INTRODUCTION  11 

this  affliction  from  every  angle  is  therefore  a 
worthy  enterprise.  It  is  at  least  a  problem  of 
the  rural  districts  of  the  Middle  West  that  is 
neither  well  handled,  nor,  so  far  as  we  can  per- 
ceive, intelligently  studied. 

The  loss  in  horses  in  Illinois  from  fistulse 
alone  reaches  into  the  thousands.  The  loss  to 
veterinarians  from  their  helplessness  in  han- 
dling the  cases  and  the  discredit  this  state  of 
helplessness  brings  to  the  veterinary  profession 
are  matters  to  be  thoughtfully  considered. 

The  fact  that  the  treatment  of  poll-evil  is  no 
longer  an  unsolved  problem  in  veterinary  sur- 
gery, and  that  this  treatment,  now  standard 
for  more  than  ten  years,  has  proved  as  nearly 
universally  successful  as  any  surgical  depart- 
ure can  prove,  and  the  further  fact  that  this  ail- 
ment differs  from  fistula  of  the  withers  only  in 
matters  governed  by  the  location,  should,  it 
seems  to  us,  have  spurred  veterinarians  to  re- 
sort to  similar  measures  for  handling  both.  The 
fact  that  the  latter  is  located  in  a  more  com- 
plex region  and  requires  an  operation  of  great- 
er magnitude  is,  we  believe,  the  only  reason 
why  no  advance  has  been  made  in  its  treat- 
ment. 

Better  surgery  from  every  angle  by  which 
good  surgery  is  judged  (anesthesia,  restraint, 
asepsis,    hemostasis    and    wound    treatment) 


12  INTRODUCTION 

will,  we  believe,  eventually  solve  the  problem 
of  fistula  of  the  withers  in  the  same  way  that 
the  much  simpler  operation  has  solved  that  of 
poll-evil. 


THE  WITHERS 

The  region  of  the  anatomy  called  the  withers 
has  no  well  defined  limits.  The  word  "with- 
ers," therefore,  while  academic  in  hippology, 
is  not  usually  found  indexed  in  text  hooks  on 
anatomy.  It  is  described  as  to  shape  in  the 
study  of  types,  but  seldom  as  regards  to  its 
component  parts,  except  in  surgical  anatomy 
- — a  branch  of  veterinary  science  that  is  as  yet 
ill-developed.  The  horse  judge  studies  the 
profile  of  the  withers  very  carefully  because  the 
general  appearance  of  any  given  horse  depends 
a  great  deal  upon  its  shape,  its  size  and  the 
measurements  of  its  dimensions.  The  surgeon 
studies  not  only  its  shape  and  dimensions,  but 
its  constituent  parts  as  well  and  their  complex 
and  disadvantageous  arrangement  from  the 
surgical  point  of  view. 

It  is  important  to  note  that  the  withers  may 
be  high,  low,  narrow,  broad,  steep,  sloping, 
long  or  short,  and  that  any  two  or  three  of 
these  characteristics  combine  to  determine  the 
various  types  of  withers  of  different  individ- 
uals. Graphic  writers  in  describing  equine 
types  often  use  such  terms  as  sharp  witliers, 
low  withers,  liigli  withers,  long  withers,  thick 


14  FISTULA  AND  POLL-EVIL 

withers,  muscular  withers,  effaced  withers, 
prominent  withers,  each  of  which,  in  addition 
to  being  descriptive  in  the  study  of  profile,  is 
equally  suggestive  in  the  study  of  etiology  of 
affections  of  these  parts  and  their  surgical 
treatment.  Each  one  of  these  characteristics 
contributes  to  a  different  etiologic  factor  as 
well  as  a  different  surgical  problem. 

Boundaries 

The  withers,  although  having  ill-defined  lim- 
its, may  be  said,  for  surgical  study,  to  extend 
from  the  crest  of  the  neck  anteriorly,  to  a  point 
posteriorly,  where  the  dorsal  spines  descend  to 
the  level  of  the  back.  The  second  dorsal  spine 
may  be  selected  as  the  uniform  anterior  limit, 
but  posteriorly  no  line  can  be  drawn,  because 
some  withers  end  abruptly  toward  the  level 
of  the  back,  while  others  slope  gradually  to  a 
more  distant  posterior  point  between  the  eighth 
and  twelfth  spines.  The  highest  point  is  al- 
most universally  at  the  fifth  spine.  The  second 
dorsal  spine  may,  therefore,  be  said  to  repre- 
sent the  anterior  boundary,  the  fifth  spine  the 
summit  and  any  point  between  the  eighth  and 
twelfth  dorsal  spines  the  posterior  boundary. 
In  the  downward  direction,  the  withers  may  be 
said  to  descend  to  the  bodies  of  the  vertebrae 
mesially  and  to  the  distal  border  of  the  scapu- 


THE  WITHERS  15 

lar  cartilage,  (cartilage  of  prolongation)  lat- 
erally. With  these  boundaries  as  a  point  of 
departure,  each  structure  comprising  the  with- 
ers might  be  studied  per  se,  but  from  the  sur- 
gical point  of  view  its  study  en  masse  is  of  first 
importance. 

Component  Parts 

The  withers  are  composed  of  skin,  fascia, 
muscles,  ligaments,  cartilage,  bones,  blood  ves- 
sels, lymphatics  and  nerves.  These  are  com- 
bined in  a  very  complex  and  exceedingly  disad- 
vantageous manner,  since  in  situ  they  form  a 
pyramid  whose  base  is  loosely  arranged  while 
the  summit  is  dense.  The  summit  of  the  with- 
ers, under  the  skin,  is  composed  of  hard  liga- 
mentous structures  fixed  firmly  to  the  underly- 
ing bones.  From  this  point,  the  layers  of  which 
the  region  is  constituted  separate  from  each 
other  in  the  downward  direction,  permitting 
thereby  a  ready  filtration  of  pus  into  constant- 
ly deeper  and  more  inaccessible  fortresses,  and 
constituting  a  favorable  field  for  the  fruitful 
development  and  undisturbed  sojourn  of  in- 
flammatory processes  of  a  chronic  character. 
The  base  of  the  pyramid  is  bounded  laterally 
and  ventrally  by  bones  (the  scapula  and  bodies 
of  the  dorsal  vertebra)  while  anteriorly  and 
posteriorly   its   component  structures  extend 


16  FISTULA  AND  POLL-EVIL 

without  change  of  arrangement  into  the  neck 
and  back.  Thus  pus  within  the  withers  after 
filtering  downward  finds  its  only  exit  by  trav- 
eling first  in  either  of  these  two  directions,  and 
ultimately  to  the  surface  of  the  body  at  points 
remote  from  the  seat  of  development.  It  is 
this  complex  arrangement  that  affords  the  im- 
pregnable intrenchment  of  pathological  prod- 
ucts and  that  is  responsible  for  the  refractory 
character,  the  extreme  seriousness  and  the  un- 
varying chronicity  of  the  disease  known  as  fis- 
tula of  the  withers. 

The  Skin 

The  skin  covering  the  withers  possesses  noth- 
ing unusual  except  the  thickness  of  the  subcut- 
em  along  the  median  line  anteriorly  where  the 
heavy  connective  tissue  of  the  mane  begins.  Pos- 
terior to  the  summit  of  the  withers  the  skin  is  of 
normal  thickness,  but  is  separable  only  with 
difficulty  from  the  aponeurosis  of  the  fleshy 
panniculus  whose  fixed  attachment  is  at  the 
level  of  the  fourth  or  fifth  spine.  Very  often, 
however,  the  skin  is  the  seat  of  scars  superven- 
ing harness  and  collar  injuries  which  fuse  it 
into  the  underlying  ligaments,  fascia  or  mus- 
cles as  the  location  may  determine. 

Panniculus  Carnosis    (Cutaneous  Muscle) 

This  muscular  structure  is  a  prominent  feat- 
ure of  the  withers  in  that  its  chief  attachment 


THE  WITHERS  17 

is  to  the  summit.  Along  the  region  of  the  with- 
ers its  fibers,  unhke  those  of  any  other  part  of 
the  body,  are  vertical,  extending  downward  to 
the  proximal  border  of  the  scapular  cartilage, 
where  they  find  another  fixed  attachment.  It 
is  fused  with  and  in  fact  may  be  regarded  a 
part  of  the  superficial  fascia.  As  a  structure 
to  incise  for  invasions  into  the  withers  it  may 
be  so  considered.  Beneath  the  superficial  fas- 
cia is  another  aponeurotic  layer  whose  fibers 
are  so  arranged  as  to  cross  those  of  the  tra- 
pezius beneath  at  right  angles.  This  layer  is 
of  no  special  surgical  importance.  It  is  found 
only  in  a  careful  dissection  of  the  region  and  is 
in  no  way  influential  in  guiding  pathological 
processes  nor  in  shaping  surgical  procedure. 

The  Trapezius 

The  trapezius,  excluding  the  fascia  just 
mentioned,  is  the  third  layer  of  the  withers  and 
is  really  the  first  of  the  anatomical  structures 
that  must  be  reckoned  with  in  the  study  of  fis- 
tula. It  is  a  triangular  membranous  muscle 
with  its  base  upward  running  along  the  withers 
where  its  aponeurosis  is  attached  to  the  supra- 
spinous ligament  along  the  withers  and  to  the 
ligamentum  nuchse  in  the  cervical  region,  ex- 
tending in  all  from  the  axis  to  the  tenth  dorsal 
vertebra.     This  triangidar  sheet-like  structure 


18  FISTULA  AND  POLL-EVIL 

is  bisected  vertically  with  a  central  aponeurosis 
that  is  attached  ventrally  to  the  tuber  spinse  of 
the  scapula.  The  anterior  part  is  the  trapezius 
cervicalis  and  the  posterior  the  trapezius  thora- 
calis. 

The  Roof  of  the  Withers 

Together  with  the  skin,  the  fascia  arid  the 
panniculus  carnosis,  the  trapezius  muscles  may 
he  regarded  as  the  'Woof  of  the  withers'' 

It  is  under  this  roof  that  typical  fistula  of 
the  withers  develop  and  beneath  which  the 
atypical  (traumatic)  fistulge  burrow  in  direc- 
tions of  resistance  less  than  that  afforded  by 
its  dense,  aponeurotic  character. 

Rhomboideus  Thoracalis 

The  rhomboideus  thoracalis  extends  from 
the  spinous  processes  of  the  second,  third, 
fourth,  fifth,  sixth  and  seventh  dorsal  verte- 
brae in  a  downward  and  outward  direction  to 
the  mesial  face  of  the  scapular  cartilage.  It 
constitutes  a  thick,  heavy  curtain  forming  a 
"second  or  inner  roof  of  the  withers."  Com- 
pared with  the  structures  of  a  building,  it 
might  be  said  to  be  a  curtain,  sagging  slightly 
in  the  middle,  that  extends  from  the  comb  of 
the  roof  to  a  point  on  the  wall  just  beneath  the 
plate  beam.    It  is  very  loosely  attached  to  the 


THE  WITHERS  19 

mesial  face  of  the  trapezius  laterally  and  to  the 
longissimus  dorsi  ventrally  and  spinalis  dorsi 
mesially  and  ventrally.  Secondary  abscesses 
of  fistul^e  of  the  withers  said  to  be  located  "un- 
der the  scapula"  are  in  reality  located  under 
this  muscle,  resting  upon  the  longissimus  dorsi 
but  without  any  obstacle  against  the  filtration 
of  pus  further  down  than  under  the  upper  part 
of  the  serratus  dorsi.  Pus  seldom  goes  to  a 
lower  level  because  the  latter  muscle  is  at- 
tached firmly  to  the  costal  surface  and  above  to 
the  mesial  face  of  the  scapula,  forming  a  space 
having  a  firm  floor  but  without  anterior  and 
posterior  walls. 

Rhomboideus  Cervicalis 

The  rhomboideus  cervicalis  is  the  forward 
elongation  of  the  thoracalis,  extending  toward 
the  head  along  the  ligamentum  nuchse  as  far 
forward  as  the  axis.  Its  insertion  is  the  an- 
terior part  of  the  mesial  face  of  the  cartilage  of 
prolongation.  Its  surgical  importance  lies  in 
the  fact  that  its  ventral  margin  just  in  front  of 
the  scapula  affords  a  point  of  invasion  into  the 
seat  of  a  typical  fistula  (Fig.  2).  It  is  also  so 
closely  related  to  the  ligamentum  nuchcT  that 
it  seldom  escapes  attack  from  the  morbid  pro- 
cess, and  when  heedlessly  sacrificed  in  resect- 
ing the  ligamentum  nucha?  a  pronounced  de- 


20  FISTULA  AND  POLL-EVIL 

formation  of  the  crest  of  the  neck  (ewe-neck) 
results.  It  may  be  said  to  reinforce  the  "roof 
of  the  withers"  anteriorly. 

Other  Structures  Important  Surgically 

The  splenius  and  the  serratus  cervicis  are 
related  to,  in  fact  occupy,  the  anterior  part  of 
the  withers.  They  lie  immediately  below  the 
rhomboideus  cervicalis  and  beneath  the  trap- 
ezius cervicalis.  Their  upper  margins  are  re- 
lated to  the  former.  Just  in  front  of  the  car- 
tilage of  prolongation  they  are  very  looseh^ 
attached  to  the  rhomboideus  and  thus  afford 
the  portal  for  surgical  invasion  above  referred 
to:  They  are  thick,  tuberous  curtain-like  mus- 
cles forming  the  bulk  of  the  crest  of  the  neck 
and  on  account  of  their  thickness  prevent 
facile  direct  invasion  to  the  bottom  of  pus  ca- 
vities which  are  usually  located  below  this  mar- 
gin at  the  level  of  the  second  dorsal  spine. 
These  two  thick  muscles,  in  short,  form  the 
lower  part  of  the  lateral  walls  of  the  pus  cav- 
ity in  fistula  of  the  withers.  The  treatment  of 
fistula  of  the  w^ithers  would  be  a  lesser  problem 
if  the  pus  cavity  could  be  drained  over  the  dor- 
sal margin  of  these  muscles  instead  of  through 
them. 

The  longissimus  dorsi.  The  longissimus  dorsi 
at  the  withers  occupies  the  space  between  the 


THE  WITHERS  21 

rhomboideus  and  the  complexus  and  spinatus. 
These  three  muscles  may  be  said  for  descrip- 
tive purposes  to  fill  in  the  angular  space 
formed  by  the  ribs  and  vertebral  spines. 

Structures  of  Lesser  Surgical  Importance 

The  complexus  anteriorly  and  the  spinalis 
dorsi  posteriorly  have  no  especial  surgical  sig- 
nificance, except  that  the  former  lies  closely 
attached  both  to  the  lamellar  and  the  funicu- 
lar 23ortions  of  the  ligamentum  nuch^  and  the 
latter  to  the  spines  of  the  vertebra  and  are 
therefore  implicated  in  disease  processes,  and 
besides  being  just  two  more  structures  to  form 
channels  for  the  burrowing  of  pus  they  in  no 
way  govern  the  course  of  surgical  operations. 
In  fact  pus  cavities  that  have  formed  beneath 
these  muscles  are  inaccessible  and  disease  of 
the  structures  between  them  (bones  posteriorly 
and  the  lamellar  portion  of  the  ligamentum 
nuchas  anteriorly)  usually  constitutes  an  in- 
curable condition. 

Viewed  as  a  Whole 

The  muscles  of  the  withers  viewed  with  the 
purpose  of  standardizing  surgical  procedure 
against  fistula  may  be  compared  to  an  irregu- 
larly-shaped covered  trough  containing  a 
longitudinal  partition.  Anteriorly  the  trough 
is  walled  by  the  splenius  and  the  serratus  cer- 


22  FISTULA  AND  POLL-EVIL 

vicis,  posteriorly  by  the  serratus  thoracis  and 
the  scapular  cartilage.  Its  floor  is  formed  by 
the  longissimiis  dorsi  and  its  roof  by  the  trap- 
ezius and  rhomboideus.  The  central  partition 
is  constituted  of  the  dorsal  spines,  spinalis  dorsi 
posteriorly  and  the  lamellar  portion  of  the 
ligamentum  nuchse  covered  with  the  com- 
plexus  anteriorly.  The  bottom  of  the  trough 
which  must  be  reached  for  effectual  drainage 
can  be  penetrated  only  with  difficulty  and  the 
risk  of  inviting  complications  in  structures  not 
previously  implicated.  Furthermore,  these 
muscles  being  in  constant  use  in  locomotion, 
respiratory  acts  and  movements  of  the  neck, 
tend  to  encourage  the  burrowing  of  pus  into 
still  more  inaccessible  recesses. 

Thus  we  find  the  musculature  of  primal  im- 
portance in  any  study  of  fistula  of  the  withers. 
It  bounds  initial  abscess  cavities  in  places 
difficult  of  access  for  drainage,  they  move  upon 
each  other  and  favor  the  distribution  of  puru- 
lent products  into  new  fields,  where  secondary 
abscesses  are  formed,  and  it  exhibits  a  remark- 
able trend  toward  fibrosis  under  the  influence 
of  the  chronic  inflammation  of  adjacent  parts. 

The  Ligaments 

The  ligaments  implicated  in  fistula  of  the 
withers  are  the  ligamentum  nuch^e  and  the 


THE  WITHERS  23 

supraspinous  ligament,  each  of  which  is  but  a 
continuation  of  the  other;  the  dorsoscapular; 
and  the  interspinous  hgaments,  which  curtain 
off  the  spaces  between  the  spinous  processes. 

The  hgamentum  nuchge  is  a  strong,  powerful 
apparatus  conij)osed  of  yellow  elastic  tissue  and 
divided  into  two  distinct  parts:  the  funicular 
portion  and  the  lamellar  portion.  The  former 
which  is  of  especial  importance  in  fistula  of  the 
withers  and  poll-evil,  extends  from  the  occip- 
ital bone  anteriorly  to  the  summit  of  the 
withers  posteriorly  where  it  becomes  white 
fibrous  tissue  and  is  continued  over  the  spines 
of  the  sacrum  as  the  posterior  part  of  the  sup- 
raspinous ligament.  It  is  composed  of  two 
lateral  halves  each  of  which  is  heavy  and 
flattened  at  the  withers  but  gradually  becom- 
ing round  and  somewhat  smaller  toward  the 
occipital  crest  to  w^hich  it  is  attached  to  the 
occipital  protuberance.  Two  bursge  are 
found  associated  with  this  structure — one 
at  the  atlas  and  the  other  in  the  dorsal  region. 
The  atlantal  bursa  is  the  seat  of  poll-evil  while 
the  dorsal  or  supraspinous  bursa  is  the  location 
of  typical  fistula  of  the  withers.  The  atlantal 
lies  between  the  ligament  and  the  dorsal  sur- 
face of  the  atlas.  Tlie  dorsal  bursa  is  usually 
over  the  third  dorsal  spine  but  sometimes  ex- 
tends backward  as  far  as  the  crest,  that  is,  over 


24  FISTULA  AND  POLL-EVIL 

the  fourth  and  the  fifth  spines,  and  often  as 
far  forward  as  the  second.  It  is  at  the  level  of 
the  second  dorsal  spine  where  the  causative 
center  of  most  of  the  cases  of  fistula  of  the 
withers  that  we  have  examined  carefully,  were 
located. 

An  important  point  to  remember  about  the 
funicular  portion  of  the  ligamentum  nuchas  is 
its  wide  expansion  posteriorly.  Approaching 
the  crest  of  the  withers  it  extends  in  the  out- 
ward and  downward  direction  five  to  six  inches, 
partly  enveloping  the  rhomboideus  and  tra- 
pezius. This  expanded  portion  is  often  the 
cause  of  recurrence  of  fistula  after  the  main 
portion  has  been  removed. 

It  is  surmounted  along  its  course  by  the 
"pad  of  the  mane"  a  structure  composed  of 
elastic  fibers  interspersed  with  adipose  tissue. 
It  is  most  abundant  in  the  middle  of  the  cervi- 
cal region  and  is  best  developed  in  stallions  of 
the  draft  breeds. 

The  funicular  portion  is  a  sheet-like  par- 
tition dividing  the  superior  cervical  muscles 
into  halves.  It  is  composed  of  two  layers 
attached  loosely  to  one  another  by  areolar  tis- 
sue, and  each  layer  is  composed  of  two  parts, 
anterior  and  posterior.  The  anterior  part  is 
thick  and  strong,  attached  to  the  funicular 
portion  above  and  to  the  cervical  spinous  proc- 


THE  WITHERS 


25 


.^< 


;f% 


^,  X  W 


.h 


.r 


H' 


Pig.  1— Ligamentum  Nuche  of  Horse. 
Note  particularly  the   relation   of  the   funicular  portion  of 
the  ligamentum  nuche   to  the  atlas  and  to  the  spines  of  the 
thoracic    vertebrae.      Also    the    arrangement    of    the    lamellar 
portion.      (After  Sisson.) 


26  FISTULA  AND  POLL-EVIL 

esses  below.  The  posterior  part  is  attached  to 
the  second  and  third  dorsal  spines  and  extends 
in  the  form  of  several  digitations  forward  and 
downward  where  its  brush-like  fibers  reach  the 
spines  of  the  fifth  and  sixth  cervical  segments. 
The  fibers  of  the  ligament  are  more  spare  than 
in  the  anterior  part  and  sometimes  do  not  even 
reach  the  sixth  vertebra.  Between  the  anterior 
and  the  posterior  parts  is  a  space  of  consider- 
able dimensions  which  especialh^  in  horses  of 
good  flesh  contains  a  mass  of  fatty  tissue.  This 
opening  is  at  the  level  of  the  extremity  of  the 
second  dorsal  spinous  process  and  is  the  seat 
of  typical  fistula  of  the  withers.  It  is  the  space 
where  the  sacculation  of  fistula  begins. 

The  supraspinous  ligament  is  a  structure 
composed  of  white  fibrous  tissue  and  extends 
along  the  dorsal  region  to  the  sacrum.  It  is 
the  continuation  of  the  ligamentum  nucha? 
posteriorly.  A  careful  dissection  of  this  struc- 
ture fails  to  show^  that  it  begins  as  an  independ- 
ent structure,  as  its  fibers  although  they  change 
in  structure  from  yellow  elastic  to  white  fibrous 
tissue,  are  simply  continuations  of  each  other. 
From  the  surgical  standpoint  the  supraspinous 
Hgament  and  the  ligamentum  nuchge  must  be 
regarded  as  a  single  apparatus  which  changes 
in  the  character  of  its  tissue  at  the  crest  of  the 
withers.    Over  the  crest  it  is  a  verv  thick,  dense 


THE  WITHERS  27 

structure  and  along  its  whole  course  backward 
it  is  attached  firmly  to  the  summits  of  the 
spines. 

The  interspinous  ligaments  are  thin  mem- 
branous structures  connecting  the  spines  to  one 
another  and  completely  filling  in  the  space 
between  them  from  the  bodies  to  the  supraspi- 
nous ligament  above,  and  thus  completing  a 
perfect  partition  between  the  two  halves  of  the 
withers 

The  dorso-scaj)ular  ligament  is  a  reflection 
of  the  superficial  fascia.  It  is  a  thick  aponeu- 
rosis attached  dorsally  to  the  crest  of  the 
withers  and  passing  outward  and  downward 
under  the  rhomboideus  to  the  scapula  and 
giving  off  layers  which  pass  between  the  under- 
lying muscles — the  longissimus  and  spinalis. 
At  the  crest  it  is  really  the  aponeurotic  origin 
of  both  the  rhomboideus  thoracalis  and  the 
splenius. 

The  importance  of  these  ligaments  in  fistula 
of  the  withers  lies  in  the  fact  that  they  are 
implicated  in  the  disease  more  commonly  than 
the  other  component  parts.  Lying  adjacent  to 
the  initial  seat  of  the  inflammatory  process, 
and  being  but  poorly  nourished  structures,  they 
fall  an  easy  prey  to  microbic  products,  becom- 
ing riddled  with  necrotic  areas  and  thus  pre- 
venting   cicatrization    of    contiguous    abscess 


28  FISTULA  AND  POLL-EVIL 

cavities.  In  poll-evil  it  is  the  anterior  part  of 
the  funicular  portion  of  the  ligamentum 
nuchge  that  prevents  healing,  while  in  fistula 
of  the  withers  it  is  the  posterior  end  or  its  liga- 
mentous continuation — the  supraspinous  liga- 
ment— that  is  implicated. 

Cartilsiges  of  the  Withers 

The  cartilaginous  tissue  included  among  the 
component  parts  of  the  withers  is  found  in  the 
scaj)ular  cartilage  (cartilage  of  prolongation) 
and  in  the  semi-cartilaginous  summits  of  the 
dorsal  spines. 

The  scapular  cartilage  which  is  attached  to 
the  vertebral  border  of  the  scapula  is  a  wide 
expanse  of  hyaline  cartilage  about  two  inches 
wide  extending  from  the  cervical  to  the  dorsal 
angle.  It  is  thick  at  the  attachment  to  the 
bone  but  becomes  thin  toward  its  vertebral 
border  which  presents  an  evenly  rounded  pro- 
file. Its  mesial  relations  are  the  rhomboideus 
and  the  serratus  ventralis  and  its  lateral  the 
trapezius  and  the  attachment  of  the  panniculus 
carnosis.  To  these  muscles  it  is  intimately 
related,  being  in  fact  imbedded  in  them.  It 
forms  the  lateral  wall  of  many  of  the  secondary 
abscesses  of  fistula  and  its  cervical  angle  and 
sometimes  its  vertebral  border  becomes  impli- 
cated in  the  disease.    By  becoming  divested  of 


THE  WITHERS  29 

its  muscular  attachments  and  perichondrium  it 
plays  the  role  of  a  foreign  body  and  thus  per- 
petuates secondary  fistulous  tracts,  which,  on 
account  of  the  movement  to  and  fro  are  very 
slow  to  cicatrize,  even  after  the  necrotic  parts 
have  been  extirpated. 

Cartilage  is  found  on  the  spinous  processes 
of  the  third,  fourth,  fifth,  sixth  and  seventh 
spines,  but  is  most  abundant  on  the  fifth  and 
sixth.  To  this  cartilage  is  fused  the  fibers  of 
the  supraspinous  ligament.  When  the  liga- 
ment detaches  from  disease  the  cartilaginous 
ends  lie  bare  and  being  soft  often  induce  sur- 
geons to  indulge  in  reckless  curetting  when  no 
such  procedure  is  indicated.  Protruding  like 
stumps  into  the  bottom  of  the  abscess  cavity 
and  being  slow  to  separate  from  the  viable 
bone  beneath,  these  cartilaginous  summits  are 
exceedingly  instrumental  in  delaying  cicatriza- 
tion and  a  prolific  source  of  recurrences. 

Bones 

The  bones  of  the  withers  are  the  spinous 
processes  of  the  dorsal  vertebra  from  the  sec- 
ond to  the  point  posteriorly  where  they  reach 
the  level  of  the  back.  They  incline  backward. 
They  are  thin  at  the  anterior  border,  thick 
posteriorly  and  expanded  dorsally  to  receive 
the  attachment  of  the  supraspinous  ligament. 


30  FISTULA  AND  POLL-EVIL 

They  increase  in  length  from  the  first  to  the 
crest  (the  fifth)  and  then  gradually  diminish 
to  the  twelfth.  Those  immediately  over  the 
crest  exhibit  the  cartilaginous  ends  above  men- 
tioned. The  increase  in  length  is  not  symmet- 
rical, the  second  being  almost  twice  as  long  as 
the  first. 

They  are  connected  to  one  another  by  the 
interspinous  ligaments  which  complete  an  im- 
pervious partition  between  the  two  lateral 
halves  of  the  withers.  Laterally  they  are  cov- 
ered with  the  spinalis  and  longissimus  dorsi 
muscles. 

The  spinous  processes  rank  high  in  impor- 
tance in  the  study  of  fistula  of  the  withers.  The 
initial  pathological  jDrocess  of  typical  fistula  is 
usually  seated  on  the  second  and  third  seg- 
ments. The  cyst  which  constitutes  the  first 
pathological  change  is  attached  to  them  and 
when  opened  often  exposes  their  cartilaginous 
summits.  In  traumatic  fistula  originating 
from  superficial  wounds,  these  processes  often 
become  the  seat  of  a  stubborn  osteitis  that 
descends  into  the  cancellated  tissue,  sometimes 
as  far  down  as  the  bodies  of  the  vertebra, 
creating  very  chronic  if  not  always  incurable 
conditions. 

The  student  of  surgical  anatomy  should 
remember  their  length  at  the  different  points, 


THE  WITHERS  31 

their  cartilaginous  summits,  their  backward 
direction,  their  connecting  media  and  the  con- 
tiguous musculature. 

Blood   Vessels 

The  withers  receives  its  blood  supply  chiefly 
from  two  sources:  the  dorsal  and  the  deep 
cervical  arteries.  Both  are  direct  radicals  of 
the  brachial  arteries,  or  more  correctly  speak- 
ing, the  left  one  arises  from  the  left  brachial 
artery  and  the  right  one  from  that  part  of  the 
same  vessel  on  the  right  side  while  it  still  bears 
the  name  brachiocephalic  artery.  The  origin 
of  both  is  within  the  thorax.  The  dorsal 
enters  the  region  of  the  withers  through  the 
second  intercostal  space  and  the  deep  cervical, 
through  the  first.  Both  of  them  leave  the 
thorax  near  the  bodies  of  the  vertebrae.  Their 
extra- thoracic  distribution  alone  interests  us, 
in  surgery  of  the  withers. 

Ecctra-tlioi'acic  distiihution  of  the  dorsal 
artery.  After  emerging  from  the  thorax 
through  the  second  intercostal  space  it  passes 
under  the  longissimus  dorsi  in  an  upward  and 
backward  direction,  soon  dividing  into  several 
branches.  The  largest  anterior  branch  passes 
forward  and  upward  under  the  splenius; 
extending  branches  anastomose  with  the  deep 
cervical  or  are  lost  in  the  deep   muscles  of 


32  FISTULA  AND  POLL-EVIL 

the  cervical  region.  The  posterior  branches 
pass  upward  between  the  dorso-seapiilar  Hga- 
ment  and  the  rhomboideus  and  thence  to  the 
snperficial  mnscles  and  skin.  These  radicals 
are  normally  small  vessels,  bnt  in  old  fistula 
they  are  often  enlarged  into  arteries  of  a 
formidable  capacity.  The  main  trunk  lying 
deeply  in  the  base  of  the  withers  is  seldom 
exposed  in  surgical  operations.  The  variation 
in  the  distribution  of  these  branches  and 
especially  the  enlargement  of  some  of  them 
under  the  influence  of  disease  make  the  study 
of  the  blood  supply  of  the  withers  somewhat 
unsatisfactory  from  the  surgical  standpoint. 
There  is  always  a  pronounced  difference  in  the 
amount  of  bleeding  produced  from  incisions 
of  exactly  the  same  kind. 

The  eoctra'tJioracic  distiihution  of  the  deep 
cervical  artery. — Emerging  from  the  fiist 
intercostal  space,  it  passes  upward  and  for- 
ward between  the  lamellar  portion  of  the 
ligamentum  nuchge  and  the  complexus.  It 
destination  is  the  region  of  the  poll  where  it 
anastomoses  with  branches  of  the  occipital. 
Along  its  course  along  the  neck  it  exhibits  free 
commimications  with  the  vertebral  and  sup- 
plies by  lateral  branches  the  lateral  cervical 
muscles.  These  lateral  branches  of  the  deep 
cervical  which  enter  the  splenitis  and  serratus 


THE  WITHERS 


33 


Fig.  2. — Deep  Dissection  of  Neck  of  Horse. 
A.     Deep   Cervical   Artery.     (After   Sisson.) 


84  FISTULA  AND  POLL-EVIL 

cervicis  in  the  region  of  fistula  of  the 
withers  are  often  enlarged  into  vessels  of  con- 
siderable dimensions. 

The  vertebral  artery, — The  vertebral  artery 
which  emerges  from  the  thorax  in  front  of  the 
first  rib  passes  between  the  longus  colli  and 
the  scalenus,  and  thence  along  the  vertebral 
column  through  the  foramina  transversaria.  At 
the  axis  it  anastomoses  with  the  occipital  and 
along  its  course  supplies  numerous  branches 
to  the  musculature,  of  both  the  dorsal  and 
ventral  cervical  regions.  The  former  anasto- 
moses freely  with  branches  of  the  deep  cervical. 

This  artery  is  of  no  great  importance  in 
surgery  of  the  withers  on  account  of  its  deep, 
protected  location.  That  its  branches  are 
capable  of  undergoing  enlargement  must, 
however,  be  considered  in  operations  invading 
the  region  of  the  vertebral  column,  as  for 
example  in  attempts  to  establish  a  drainage 
of  abscess  cavities  resting  on  the  bodies  of  the 
vertebrae  (cervical  fistula). 

The  Nerves 
The  nerves  of  the  withers  are  both  cranial 
and  spinal.  Sensation  is  supplied  by  the  dor- 
sal branches  of  the  thoracic  and  cervical  spinal 
nerves  while  the  motor  supply  is  derived  not 
only  from  those  mixed  nerves  but  also  from 


THE  WITHERS  36 

the  spinal  accessory — the  eleventh  cranial — 
nerve. 

The  spinal  nerves  are  seldom  exposed  to 
view  in  surgery  of  the  withers  and  as  they  have 
a  promiscuous  distribution,  loss  of  motor 
power  is  never  observed  from  incision  of  the 
trunks  or  their  ramuli. 

The  spinal  accessory  being  the  chief  motor 
supply  of  the  trapezius  and  lying  in  a  super- 
ficial position  may  be  incised  in  making  reck- 
less vertical  incision  over  the  lateral  surface 
of  the  scapula  below  the  scapular  cartilage. 
Its  division  while  not  attended  with  any  pro- 
nounced harm  is  inadvisable  on  the  general 
grounds  that  large  muscular  areas  should  not 
be  unnerved. 

The  Lymphatic  Systein  of  the  Withers 

This  may  be  said  to  include  the  intercostal 
nodes  of  this  region  and  the  prescapular  nodes, 
together  with  their  afferent  vessels. 

The  intercostal  nodes  are  located  at  the 
intercostal  spaces  at  each  side  of  the  vertebrae, 
and  they  receive  vessels  arising  chiefly  in  and 
among  the  dorsal  muscles.  They  are  small  in 
the  normal  state  but  in  fistula  of  the  withers 
they  become  larger  and  may  even  suppurate  or 
become  the  initial  seat  of  a  secondary  pleuritis, 


36  FISTULA  AND  POLL-EVIL 

The  afferent  vessels  empty  directly  into  the 
thoracic  duct. 

The  prescapidar  glands  receive  afferent  ves- 
sels from  the  skin  of  the  anterior  part  of  the 
withers  and  also  from  the  superficial  muscles 
of  the  neck.  The  afferent  vessels  lead  to  the 
posterior  cervical  nodes  and  thence  to  the  tho- 
racic duct. 


PATHOGENESIS 

There  are  two  kinds  of  fistulce  of  the 
withers.  One  is  the  tijpical  or  idiopathic  form 
and  the  other  is  the  atypical,  traumatic  or 
symptomatic  form.  The  first  or  typical  has  its 
origin  in  the  development  of  a  serous  sac  or 
cyst  under  the  ligamentum  nuch«  at  the  level 
of  the  second  or  third  dorsal  spines,  while  the 
second  or  atypical  is  caused  by  an  external 
wound  that  serves  as  a  portal  of  entrance  for 
microorganisms.  In  the  first  stages  these  tw^o 
forms  differ  very  materially  in  every  respect 
but  in  the  final  stage  they  are  alike  in  that  both 
of  them  cause  disease  of  the  ligamentum 
nuch«  or  its  backward  extension  (the  supra- 
spinous ligament)  and  sometimes  the  spines  of 
the  vertebra  themselves.  In  short,  each  form 
finally  plays  the  same  havoc  upon  these  struc- 
tures, although  they  have  an  entirely  different 
pathology  at  the  beginning.  Fistula  of  the 
withers  in  the  final  stage  might  be  properly 
called  necrosis  of  the  ligamentum  nuchae  or  of 
the  supraspinous  ligament  according  to  its 
cephalo-caudal  location.  In  the  typical  form 
it  is  the  ligamentum  nuchae  that  is  chiefly 
affected    while    the    traumatic     form,    being 


38  FISTULA  AND  POLL-EVIL 

usually  due  to  harness  bruises,  reflects  more 
upon  that  part  of  the  region  occupied  by  the 
supraspinous  ligament.  The  disease  pro- 
gresses in  many  cases  from  one  to  the  other  of 
these  two  structures  by  extension  of  the  dis- 
ease process  in  one  direction  or  the  other 
according  to  the  initial  seat.  That  is  to  say,  a 
fistula  beginning  in  a  cyst  at  the  level  of  the 
second  dorsal  spine  may  attack  the  liga- 
mentum  nucha  above  that  level  and  then 
travel  backward  into  the  supraspinous  liga- 
ment, while  on  the  other  hand  a  harness  bruise 
may  cause  a  disease  of  the  supraspinous  liga- 
ment at  the  level  of  the  saddle  seat  that  will 
travel  forward  into  the  ligamentum  nuchge. 
In  fact,  all  old  cases  have  this  dual  involvement 
and  often  the  spines  beneath  are  found  necrotic. 

The  Typical  Form 

To  make  our  study  more  comprehensive  we 
shall  divide  the  development  of  this  form  of 
fistula  into  three  stages,  namely:  The  saccu- 
lar stage,  the  phlegmonous  stage  and  the 
fistulous  stage. 

1.  Saccular  Stage.  This  is  the  initial  one.  It 
has  its  origin  in  the  accumulation  of  serosity 
upon  or  adjacent  to  one  of  the  dorsal  spines, 
usually  the  second.  Beginning  with  this  col- 
lection of  serum,   which   is   sero-fibrinous    in 


PATHOGENESIS  39 

character,  it  gradually  enlarges  into  a  cyst  of 
larger  and  larger  dimensions  until  it  becomes 
clinical  by  bulging  at  the  surface  of  the  base 
of  the  neck  or  at  a  point  of  least  resistance 
adjacent  thereto.  The  sac  is  at  first  very  small 
and  without  any  well  developed  limiting  mem- 
brane but  as  it  becomes  larger  the  tissues  react 
to  the  encroachment  by  forming  a  firm  con- 
nective tissue  layer  around  it  and  at  the  same 
time  fibrin  and  cells  attach  themselves  to  the 
inner  wall  and  thus  pave  it  with  a  smooth 
carpet  that  completes  a  firm  encapsulation  of 
the  liquid  contents.  The  amount  of  connective 
tissue  contained  in  the  encapsulating  structure 
varies  with  the  chronicity  of  the  process.  In 
old,  slotdy  forming  cases  the  fibrous  elements 
may  form  in  large  quantities,  encroaching  upon 
the  capacity  of  the  sac  internally  and  gradually 
bulging  exteriorly  until  the  lesion  is  in  fact 
more  fibrous  than  cystic.  Thus  ice  have  the 
large  fistulae  of  the  icithcrs  in  tchich  fibrosis  is 
the  dominating  feature.  This  sac  is  uniformly 
related  to  one  of  the  dorsal  spines,  usually  the 
second,  but  sometimes  the  third  and  in  rare 
cases  the  fourth  or  even  the  fifth.  We  have 
never  seen  a  typical  fistula  of  the  withers  orig- 
inate farther  back.  Those  located  on  the  sum- 
mit or  further  back  are  always  of  the  other 
variety  (traumatic  or  atypical).    The  point  of 


40  FISTULA  AND  POLL-EVIL 

predilection  of  typical  fistula  of  the  withers  is 
stubbornly  anterior  to  the  summit  of  the 
withers — in  the  space  where  tlie  spines  decline 
abruptly  into  the  cervical  region. 

The  sac  forms  slowly  and  without  apparent 
pain  or  discomfort  to  the  patient.     We  have 
found  ample  evidence  post-mortem  in  subjects 
that  have  died  from  other  causes  that  cysts  of 
this  character  sojourn  here  without  attracting 
attention.     They  are  too  small  to  bulge  ex- 
ternally and  cause  no  distress  that  would  at- 
tract one's  attention  to  them.     These  hidden 
cysts  are  sometimes  the  size  of  an  egg  and 
sometimes  as  large  as  a  base  ball,  and  when 
old  are  so  well  encapsulated  as  to  prevent  fur- 
ther development.     Thus  cysts  may  never  de- 
velop into  fistuhe  or,  in  other  words,  the  sac- 
cular stage  may  never  advance  into  the  fis- 
tulous   stage.      The    process    is    arrested    by 
encapsulation  and  later  the  fluid  content  is  re- 
abs()r})ed,  leaving  no  trace  of  its  previous  ex- 
istence.    The  resulting  cicatrical  tissue  is  lost 
in  its  connective  environment.    This  process  of 
arrested  develojnnent,  encapsulation  and  reab- 
sorpfion  occurs  also  in  clinical  cases.     Or  in 
other  words,  a  clinical  case  of  fistula  of  the 
withers  in  tlie  saccular    stage   tliat   has   never 
been   exposed   to   extraneous  microorganisms 
may  disappear  spontaneously.    It  is  tlius  that 


PATHOGENESIS  41 

liniments  and  blisters  applied  to  them  often 
are  credited  with  curative  properties  when,  in 
fact,  it  was  an  inherent  influence  that  operated 
to  that  end. 

The  duration  of  this  stage  has  been  very 
difficult  for  us  to  determine.  We  believe,  how- 
ever, that  it  is  very  irregular,  that  some  cases 
develop  very  rapidly  into  clinical  cases  while 
others  remain  almost  dormant  for  months, 
some  disappearing  entirely  and  some  bulging 
slowly  toward  the  surface. 

It  is  these  slowly  forming  ones  that  develop 
so  much  fibrous  tissue  and  thus  change  the  en- 
tire aspect  of  the  condition  from  cyst  to  neo- 
plasm. This  occurrence  seems  almost  sufficient 
reason  to  include  in  the  classification  a  third 
form  of  fistula  of  the  withers — the  fibrous 
form — if  the  reader  were  not  familiar  with  the 
remarkable  aptitude  of  horse-flesh  to  form 
fibrous  tissue  from  continued  irritation. 
Edema,  pressure,  foreign  body,  feebly  virulent 
infection,  cold  abscess,  granuloma  and  other 
tumors  in  the  flesh  of  horses  cause  the  forma- 
tion of  great  volumes  of  fibrous  tissue  luilike 
that  of  any  other  animal.  It  is  thus  that  a 
slowly  forming  fistula  beginning  in  the  depths 
of  the  neck  becomes  the  underlying  cause  of 
the  formation  of  new  tissue  in  such  abundance 


42  IISTULA  AND  POLL-EVIL 

as  is  seen  in  some  cases  of  fistula  long  before 
infection  has  entered  into  the  situation. 

Sunimarizing  the  condition  during  the  sac- 
cular stage  we  find  a  sac  containing  a  sero- 
fibrinous, sterile  exudate,  that  may  be  large 
and  surrounded  by  a  thin  capsule  or  small  and 
enclosed  in  a  very  thick  mass  of  connective  tis- 
sue. Between  these  two  extremes  we  find  the 
intermediate  varieties — for  example,  one  the 
size  of  a  child's  head  containing  a  quart  of 
fluid  and  encapsulated  with  a  fibrous  envelope 
one  incli  in  thickness ;  another  the  size  of  a  foot- 
ball with  only  a  very  thin  wall;  and  finally,  a 
rare  case  with  a  very  insignificant  cavity  sur- 
rounded with  a  great  volume  of  connective 
tissue.  Pathologically  all  of  these  are  similar, 
they  differ  only  in  the  relative  quantities  of 
the  different  elements  entering  into  their  con- 
stituent parts. 

During  this  stage  fistula  is  a  benign  disease. 
It  is  not  as  yet  infectious.  There  is  no  syste- 
matic disorder.  The  patient  suffers  no  appar- 
ent inconvenience.  Its  general  health  is 
undisturbed. 

Until  now  the  process  belongs  to  an  order  of 
pathological  conditions  no  more  understood 
than  the  growth  of  tumors.  In  fact,  it  re- 
sem])les  tumor  and  cyst  formation  in  all 
respects.     It  is  but  cellular  activity  around  a 


PATHOGENESIS  43 

fluid-containing  cavity  with  the  formation  of 
new  tissue  influenced  by  an  unknown  stimulus. 
Henceforth,  however,  a  change  occurs;  it 
passes  into  another  entirely  different  stage 
through  the  intrusion  of  pyogenic  microor- 
ganisms into  the  cavity. 

2.  Phlegmonous  Stage,  This  is  the  second 
step  in  the  development  toward  a  real  fistulous 
condition.  Inasmuch  as  there  is  no  positive  in- 
formation about  the  thoroughfare  through 
which  infection  occurs  we  shall  only  venture  an 
opinion  that  it  is  through  the  blood  stream  or 
lymph  channels  that  the  microbes  reach  their 
goal.  There  is,  of  course,  the  possibility  that 
cutaneous  bruises  from  the  collar  may  afford 
an  entrance  avenue,  but  the  fact  that  suppura- 
tion occurs  in  animals  that  have  never  been  in 
harness  and  could  not  reasonably  have  sus- 
tained contusions  of  sufficient  severity  to  cause 
subcutaneous  infection,  least  of  all,  a  still 
deeper  infection  within  the  cavity  without  any 
surface  inflammation,  leaves  no  doubt  that  at 
least  a  great  majority  of  fistulas  become  in- 
fected fi^om  witJiin.  We  have  observed  fistulee 
develop  rapidly  from  the  saccular  to  the  phleg- 
monous stage  following  influenza,  especially 
complicated  influenza.  In  fact,  fistula  of  the 
withers  might  with  all  reason  be  included  as 
one  of  the  sequelae  of  influenza.     The  large 


44  FISTULA  AND  POLL-EVIL 

number  of  remounts  that  develop  this  compli- 
cation after  attacks  of  shipping  fever  confirms 
our  observation  of  twenty-five  years  of  city 
practice  in  this  connection.  The  saccula?'  stage 
of  the  disease  affords  a  fertile  field  for  the 
localization  of  the  microbes  in  the  germ-ridden 
hodji  of  the  influenza  patient. 

Once  infected  the  patient  falls  sick  and  is 
henceforth  in  the  siege  of  an  enfeebling  disease. 
The  temperature  rises  to  102  degrees  to  104 
degrees  Fahrenheit;  depression  is  pronounced 
and  movements  of  the  body  are  painful.  Often 
the  patient  grunts  as  in  pleurisy  from  the  pain 
of  turning  the  body.  When  these  symptoms 
occur  before  there  is  any  conspicuous  surface 
swelling,  there  is  indeed  danger  of  overlooking 
the  cause  of  the  patient's  indisposition.  Or- 
dinarily the  withers  are  hot,  tumefied,  radiating 
and  painful  on  one  or  both  sides. 

The  course  of  this  stage  will  depend  upon 
the  virulence  of  the  infection,  the  fertility  of 
the  field  afforded  by  the  saccular  stage,  and  the 
natural  resistance  of  the  patient.  If  the  sac  is 
small  and  well  encapsulated  and  the  infection 
feebly  virulent,  the  process  may  be  slow  and 
even  go  on  almost  unnoticed,  all  of  tlie  while 
causing  the  formation  of  more  fibrous  tissue 
and  making  its  inroad  of  destruction  into  the 
])()()rly  nourislied  hgamentum  nuclut  and  ad- 


PATHOGENESIS  45 

jacent  structures,  coming  to  the  surface  very 
slowly.  It  is,  in  fact,  a  cold  abscess.  Some 
months  may  elapse  after  infection  has  occurred 
before  the  abscess  points  at  the  surface,  but  all 
of  the  while  ^pathological  changes  are  taking 
place  within.  JMore  connective  tissue  is  formed 
and  the  necrosis  of  the  ligament  is  extending 
forward  and  backward  from  the  seat  of  the 
abscess  which  was  originally  the  cyst.  Soaked 
in  this  infected  environment  the  dorsal  spines 
become  involved  and  sej^arate  from  the  soft 
structures  attached  to  them,  sometimes  stand- 
ing out  stump-like  into  the  cavity  until  seques- 
tration occurs.  Slowly  the  pus  finds  an  exit 
at  the  surface  of  the  body  after  burrowing  here 
and  there  in  different  directions.  The  exit 
aperture  is  not  uniformly  located.  It  may 
sometimes  appear  at  the  summit  of  the  enlarge- 
ment, but  more  often  it  is  more  remote,  the  pus 
having  traveled  between  the  different  layers  of 
fascia  and  muscular  tissue  of  this  complex- 
region  to  places  far  removed  from  the  initial 
hot-bed.  We  once  traced  a  fistulous  tract  from 
the  lumbar  region  forward  along  the  longissi- 
mus  dorsi,  under  the  scapula  to  the  level  of  the 
second  dorsal  vertebra.  Other  cases  burrow 
backward  under  the  cervical  angle  of  the  scap- 
[da  and  point  at  tlie  highest  point  of  the  withers, 
leaving  one  to  suppose  that  this  is  the  original 


46  FISTULA  AND  POLL-EVIL 

seat  of  the  trouble  as  in  the  traumatic  forms. 
This  hkelihood  of  fistulas  to  point  at  or  near 
one  side  of  the  summit  has  misled  many  a  prac- 
titioner away  from  the  actual  seat  of  the  causa- 
tive center.  In  short,  the  existence  of  the  aper- 
ture in  a  posterior  location  is  no  indication 
that  the  case  is  not  a  typical  one  centered  at 
the  usual  place,  under  the  ligament  at  the  level 
of  the  second  dorsal  spine.  The  aperture  may 
come  at  different  very  remote  points  that  are 
often  deceptive. 

The  average  case  is  more  acute.  Given  one 
with  a  sac  containing  a  quart  of  fluid  with  a  thin 
capsule  and  infected  with  virulent  microbes 
that  produce  an  acute  inflammatory  process,  a 
channel  is  soon  dissolved  directly  to  the  surface. 
Often  pointing  occurs  long  before  there  is  much 
damage  done  to  either  the  ligament  and  bones 
and  if  proper  treatment  were  instituted,  these 
might  never  become  seriously  involved.  A  cure 
could  be  effected  without  disturbing  them.  The 
cyst  is  developed,  becomes  infected  and  bursts 
at  the  surface  without  having  done  much  dam- 
age. This  is  the  most  favorable  of  all  the 
fistulae  of  the  withers  to  treat  surgicall}^  On 
the  contrary,  if  the  process  is  slow  and  there 
is  delay  in  pointing,  and  if  no  treatment  is 
instituted  to  relieve  matters,  the  disease  slowly 
but  surely  encroaches  into  the  adjacent  struc- 


PATHOGENESIS  47 

tures  and  thus  creates  a  less  favorable  con- 
dition. 

The  duration  of  this  stage  Hke  the  former 
one  is  variable.  If  the  infection  is  acute  and  the 
cyst  wall  thin,  the  abscess  may  ripen  and  burst 
in  a  few  days,  while  on  the  other  hand  if  less 
virulent  and  incarcerated  in  a  thick  wall,  point- 
ing may  be  delayed  for  weeks  and  even  months. 
When  the  abscess  has  once  found  a  surface 
exit  and  has  discharged  its  contents,  the  disease 
has  passed  into  an  entirely  different  stage,  and 
for  a  time  the  systemic  condition  improves. 

3.  Fistulous  Stage.  This  is  fistula  of  the 
withers.  Heretofore  the  condition  was  fistula 
only  in  name,  now  it  is  a  reality.  Heretofore 
the  course  of  the  disease  was  guided  solely  by 
internal  influences,  now  it  is  exposed  also  to 
secondary  infections  from  without.  It  does  not 
matter  whether  the  pointing  was  spontaneous 
or  whether  an  aperture  was  made  artificially, 
we  now  have  to  deal  with  a  deep-seated  cavity 
that  communicates  freely  with  the  outside 
where  reinfection  will  continue  to  occur,  and  to 
make  matters  still  worse  the  drainage  is  seldom 
good  enough  to  evacuate  the  contents  entirely. 
By  remaining  full  of  pus  the  cavity  becomes  a 
fertile  field  for  microbian  growth  and  cicatrizes 
very  slowly.  The  pus-soaked  walls  of  the  cav- 
ity becoming  carpeted  with  undulating  indol- 


18  FISTULA  AND  POLL-EVIL 

ent  granulations  that  encroach  slowly  on  its  ca- 
2)acity  and  without  always  showing  any  ten- 
dency to  complete  the  process  of  cicatrization 
hecause  they  must  sprout  largely  from  a  poorly 
nourished  matrix  (the  ligament)  which  now 
dies  in  foci  here  and  there,  and  then  sojourns 
only  as  a  foreign  agent  to  ])erpetuate  the 
process  indefinitely.  The  ligament,  contrary 
to  the  generally  accepted  conclusion,  is  never 
found  entirely  dead,  except  in  very  old  and  ex- 
ceptional cases;  it  undergoes  only  focal 
necrosis  at  different  spots,  retaining  enough 
vitality  to  delay  sequestration,  and  all  of  the 
while  sprouting  out  with  indolent  granulations 
over  its  viable  zones.  The  granulations  are  in- 
capable of  maturing  into  scar  tissue  because  of 
the  dead  zones  protruding  here  and  there 
among  them  and  because  they  are  poorly  nour- 
ished. Thus  we  must  not  suppose  when  w^e  say 
that  fistula  of  the  withers  is  due  to  necrosis  of 
the  ligamentum  nuch^,  that  the  ligament  is 
immediately  dead  and  that  as  a  dead  object 
perpetuates  the  disease  right  from  the  begin- 
ning. Fistula  on  the  contrary  is  due  to  the  slow^- 
ly  dying  process  of  the  ligament,  to  its  stub- 
born viability  rather  than  to  its  death.  Once 
dead,  however,  and  separated  from  the  living 
part,  the  cavity  w^ill  cicatrize  as  soon  as  the 
slough  is  removed,  encysted  or  dissolved,  pro- 


PATHOGENESIS  49 

viding  there  are  no  secondary  cavities  that  do 
not  drain. 

During  the  fistulous  stage  of  the  disease  we 
must  reckon,  therefore,  with  a  slowly  dying 
ligament,  exfoliation  of  the  ends  of  the  spines, 
the  secondary  pus  due  to  the  burrowing  of  pus 
into  adjacent  spaces  and  the  fibrosis  that  con- 
tinues to  encroach  upon  the  surrounding  mus- 
culature. It  is  plain  that  these  constitute  a 
combination  of  very  inimical  conditions.  There 
is  also  in  addition  to  these,  a  chronic  septicemia 
that  slowly  but  siu'ely  undermines  the  general 
health  and  manifestly  reduces  the  patient's 
vitality.  The  tracts  leading  from  pus  cavities 
to  the  surface  apertures,  to  still  further  com- 
plicate matters,  close  up  by  cicatrization  from 
time  to  time  and  thus  pen  up  the  pus  again  until 
it  has  burrowed  out  a  new  channel.  During 
this  occurrence  the  patient  is  again  sick  as  in 
the  phlegmonous  stage,  exhibiting  pain,  dis- 
tress in  movement,  fever  and  general  malaise. 
Each  attack  of  this  kind  leaves  the  patient  more 
enfeebled  and  still  further  damages  the  withers 
by  forming  new  tracts,  more  fibrous  tissue  and 
sometimes  new  secondary  cavities.  The  disease 
ends  in  one  of  two  ways:  the  common  one  is 
emaciation  and  death,  and  the  other  is  chronic 
fistula,  discharging  limited  amounts  of  pus  for 
several  years.     Rare  cases  heal  up  spontan- 


50  FISTULA  AND  POLL-EVIL 

eously.  Often  the  death  follows  an  operation 
postponed  too  long,  postponed  until  the  patient 
is  too  weak  to  stand  the  ordeal  of  the  extensive 
intervention  needed  to  cope  with  the  neglected 
condition. 

The  location  of  the  secondary  pus  cavities  is 
varied.  Backward  between  the  scapular  car- 
tilage and  the  dorsal  spines  as  far  back  as  the 
caudal  angle  of  the  scapula  and  under  the 
rhomboideus,  is  a  favorite  location.  Another 
place  where  pus  commonly  gathers  is  in  the 
space  under  the  scapula  just  above  the  insertion 
of  the  serratus  thoracalis,  and  sometimes  this 
same  cavity  is  diverted  also  under  this  muscle 
and  then  extends  downward  over  the  costal  sur- 
face as  far  down  as  the  sternum.  The  most 
serious  secondary  cavity,  however,  is  the  one 
that  seats  itself  in  the  cervical  region  on  the 
bodies  of  the  vertebrae  on  one  or  both  sides  of 
the  lamellar  portion  of  the  ligamentum  nucha^, 
This  one  constitutes  what  has  been  called  cervi- 
cal fistula,  a  condition  due  to  implication  of  the 
ligament  anteriorly.  When  a  large  area  of  the 
lamellar  portion  is  involved  the  neck  tumefies 
on  both  sides  and  one  or  more  tracts  form  to 
the  surface,  often  as  far  forward  as  the  middle 
third  of  the  cervical  region.  This  is  one  of  the 
most  hopeless  terminations  of  fistula  of  the 
witliers  as  the  affected  center  is  inaccessible  to 


Fig.  3. — A  Pro-nounced  Fistula  of  the  Withers. 


52  FISTULA  AND  POLL-EVIL 

any  form  of  effectual  treatment.  The  affected 
area  of  ligament  is  too  extensive  to  extirpate 
and  drainage  apertures  cannot  be  made  nor 
maintained  to  any  advantage.  In  short, 
cervical  fistula  is  an  incurable,  hopeless  con- 
dition. 

Still  another  location  is  the  bodies  of  the 
dorsal  vertebrae  between  the  scapulae.  Here 
the  pus  follows  the  spines  downward  and  seats 
itself  at  an  inaccessible  place  for  drainage. 

The  Atypical  Form 

By  atypical  fistula  we  refer  to  those  of 
strictly  traumatic  origin.  They  supervene 
saddle,  harness  and  collar  sores  and  cutaneous 
contusions  of  various  kinds,  especially  those 
due  to  a  hard,  continuous  pressure  or  deep 
pressure.  Most  of  them  begin  as  a  pressure 
gangrene  of  a  small  zone  of  the  skin,  the  sub- 
cutem  and  the  underlying  ligament.  The  mi- 
crobian  florae  of  these  lesions  are  the  usual  horde 
of  stajDhylococci  and  bacilli  that  ordinarily  hi- 
fect  woimds  of  horses.  In  one  specimen  taken 
from  our  clinic,  Prof.  Herzog  isolated  the 
Bacillus  necrophorus  in  addition  to  tlie  otliers, 
The  ligament  once  attacked  is  slowly  invaded 
farther  and  farther  along  its  course  and  the 
underlying  spines  become  implicated.  That  is. 
the  disease  once  seated  becomes  progressive, 


PATHOGENESIS  53 

because  the  cavity,  pointing  upward,  does  not 
drain  and  the  pus-soaked  dead  elements  of  the 
hgament  remaining  stubbornly  attached  to  the 
living,  favor  the  gradual  onward  march  of  the 
process  of  destruction.  Those  originating  pos- 
teriorly travel  forward  into  the  ligamentum 
nuch^  under  the  connective  tissue  of  the  mane 
and  thus  seat  themselves  at  just  the  same  point 
as  the  atypical  form,  the  chief  difference  being 
the  amount  of  bone  involvement,  which  in  the 
atypical  form  is  always  more  pronounced  than 
in  the  other.  Beginning  at  the  highest  point 
of  the  withers  from  a  serious  pressure  necrosis 
from  the  harness,  this  form  is  more  prone  to 
travel  downward  into  the  spines,  ofttimes  at- 
tacking two  or  more  of  them  with  an  acute 
destructive  osteitis  that  travels  down  toward 
the  bodies  of  the  vertebrae  casting  off  se- 
questra and  fusing  them  together  with  a  mass 
of  connective  tissue  that  is  very  slow  to  recon- 
nect itself  to  the  surrounding  integuments, 
even  after  the  pathological  process  has  other- 
wise terminated. 

Tlie  disease  is  most  common  in  horses  whose 
withers  are  thin  of  flesh  from  hard  work  and 
privation.  The  vitality  thus  reduced  is  a  dom- 
inating etiological  factor.  The  enfeebled  tissue 
becomes  the  prey  of  tlie  virulent  infection  in- 
troduced through  and  harbored  by  the  harness 


54  FISTULA  AND  POLL-EVIL 

sore.  The  local  dry  gangrene  called  sit  fast  at 
the  level  of  the  collar  seat  is  one  of  the  com- 
monest causes  as  well  as  the  initial  lesion  of  the 
very  gravest  of  fistulas  of  this  kind.  Here  the 
thick,  folded,  hair-clothed  skin  and  also  the 
thick  pad  of  connective  tissue  underlying  the 
mane  first  undergo  gangrene  from  collar  pres- 
sure. Some  of  these  sitfasts  involve  only  the 
skin  (superficial  sitfast),  others  invade  into 
the  connective  tissue  and  still  others  entirely 
through  it,  exposing  the  ligamentum  nuchse 
beneath.  From  this  exposure  the  process 
marches  on  along  the  course  of  the  ligament 
and  there  sows  the  seed  of  a  chronic  state  pre- 
cisely the  same  as  fistula  from  other  causes, 
and  requiring  the  same  remedial  measures.  In 
fact,  it  is  our  experience  that  fistula  of  this 
origin  are  the  most  stubborn  of  all. 

Once  seated  in  the  ligament  and  bones, 
atypical  fistula  is  identical  with  the  one  having 
its  origin  in  a  pre-existing  cyst  (typical  fistula) 
and  will  henceforth  undergo  the  same  course  of 
successive  abscess  and  tract  formation.  Ab- 
scesses form,  burrow  to  the  surface,  discharge 
for  a  time,  heal  up,  gather  again  and  burst  at 
another  point,  and  this  chain  of  events  may  re- 
cur indefinitely.  During  the  formation  of  a 
new  abscess  there  is  local  pain,  distressed  move- 
ments, fever  and  a  general  indisposition  just 


PATHOGENESIS  65 

the  same  as  during  the  abscess  formation  of  the 
typical  form.  There  is,  however,  never  as  much 
fibrous  tissue  formed  as  in  the  other  variety. 
Although  the  environs  of  the  tracts  and  ab- 
scess are  surrounded  by  fibrous  tissue  it  is 
never  so  abundant.  Voluminous  fibrosis  is  an 
attribute  only  of  slowly  forming  typical  fistula. 

The  secondary  pus  cavities  of  atypical  fis- 
tula are  more  superficial  than  those  of  the 
typical  kind,  particularly  during  the  early 
stages.  These  are  often  subcutaneous,  some- 
times just  under  the  superficial  fascia  and  at 
other  times  simply  under  the  trapezius,  but 
later  when  the  disease  has  become  more  deeply 
seated  and  has  traveled  anteriorly  along  the 
ligament,  they  may  be  found  in  the  same  deep 
locations  as  in  the  typical  forms.  On  the 
other  hand,  it  might  be  said  here  that  these 
superficial  abscesses  do  not  occur  except  in  the 
atypical  ones,  except  when  lancing  or  other 
improperly  directed  treatment  causes  them. 

The  differences  pathologically  between  these 
two  forms  might  be  summarized  as  follows : 

1.  Typical  fistulcC  originate  in  sterile  cysts 
located  on  or  adjacent  to  the  second  dorsal 
spine. 

2.  The  cause  of  typical  fistula  is  unknown, 
and  the  influence  under  which  the  cyst  develops 


56  FISTULA  AND   POLL-EVIL 

a  well  defined  limiting  wall  is  likewise  not  un- 
derstood.   It  simulates  tumor  formation. 

3.  Typical  fistulae  develop  deep  secondary 
abscess  during  the  early  phase  of  the  phleg- 
monous stage,  while  atypical  ones  develop  these 
only  in  the  later  stages.  The  early  abscess 
cavities  of  the  latter  are  superficial. 

4.  Fibrosis,  that  is,  the  formation  of  fibrous 
tissue  is  more  pronounced  in  the  typical  form 
and  is  never  voluminous  in  the  other. 

5.  Bone  involvement  is  more  certain  and  al- 
ways more  extensive  in  the  atypical  forms. 

6.  The  toxemia  is  more  pronounced  in  the 
early  stages  of  the  typical  form,  but  in  later 
stages  both  are  alike  in  this  connection. 


SYMPTOMS 

The  initial  stage  of  typical  fistula  of  the 
withers  develops  unnoticed.  As  long  as  the 
cyst  located  in  its  mesial  position  is  not  large 
enough  to  hulge  to  the  exterior  of  the  body  on 
one  side  or  the  other  and  before  it  has  become 
infected  with  pyogenic  microorganisms,  there 
are  no  symptoms  that  would  attract  attention 
to  the  developing  disorder  of  the  region. 
Everything  is  normal  in  appearance  and  the 
patient  suffers  no  apparent  discomfort.  Yet 
there  is  this  initial  stage  of  fistula  of  the  withers 
to  reckon  with.  How  long  the  trouble  is  de- 
veloping at  the  center  before  there  is  any 
change  in  the  profile  of  the  region  is  not  known. 
The  fact,  however,  that  we  find  on  post-mortem 
examinations  accumulations  of  a  serous  fluid 
at  the  level  of  the  second  dorsal  spine  varying 
from  small  sacs  the  size  of  an  egg  to  that  of  a 
base  ball  enclosed  in  a  feebly  developed  sac,  in 
animals  tliat  were  never  suspected  of  having 
any  such  a  condition  and  wliicli  died  from  other 
causes,  is  ample  evidence  tliat  tlie  disease  exists 
a  long  time  before  the  symptoms  begin  to  ap- 
pear. Finally,  however,  the  region  begins  to 
enlarge,  first  on  one  side  and  then  on  the  other. 


58  FISTULA  AND  POLL-EVIL 

In  rare  cases  both  sides  bulge  simultaneously. 
The  bulging  may  take  the  form  of  a  circum- 
scribed spherical  protrusion  or  it  may  be  dif- 
fuse, extending  evenly  forward  over  the  base  of 
the  neck  and  backward  over  the  withers  with 
its  crest  opposite  the  cephalic  angle  of  the 
scajiula  or  slightly  forward  from  that  point= 
When  both  sides  bulge  from  a  diffuse  enlarge- 
ment, the  withers  may  appear  enormous  in 
width  and  elevation,  sometimes  to  the  extent 
of  making  the  patient  seem  top-heavy.  If  the 
cavity  is  not  artificially  evacuated,  nor  other- 
wise molested,  the  enlargement  may  remain  un- 
changed indefinitely.  We  have  in  mind  cases 
remaining  in  the  saccular  stage  for  more  than 
two  years  with  no  other  changes  pathologically 
than  that  of  becoming  less  fluctuant  from  the 
development  of  its  fibrous  encapsulation,  and 
not  infrequently  we  have  seen  them  disappear 
entirely.  There  is  no  way  to  predict  accurately 
when  any  given  case  will  suppurate. 

Finally,  the  great  majority  of  cases  pass  into 
the  phlegmonous  stage ;  that  is,  they  become  in- 
flamed from  the  invasion  of  microorganisms. 
This  event  is  announced  by  local  pain,  radiating 
lines  extending  from  the  crest  of  the  enlarge- 
ment, indisposition  to  move,  grunting,  fever 
and  general  depression.  Cases  that  become  in- 
fected before  the  cyst  is  large  enough  to  bulge 


SYMPTOMS  59 

out  the  neck  may  prove  puzzling  in  the  absence 
of  any  pathognomic  symptom. 

Then  again  we  must  differentiate  (before 
suppuration  unmasks  the  character  of  the  ail- 
ment) fistula  from  other  enlargements  and 
growths  in  the  region.  Sarcomata  and  melan- 
osis may  localize  on  the  withers,  and  unless 
taken  into  account  there  is  some  danger  of 
error  in  diagnosis.  The  former  is,  however, 
rare  and  the  latter  is  seen  only  in  white  horses. 
A  black  work  horse,  submitted  to  the  writer  by 
Dr.  D.  JNI.  Campbell,  exhibiting  a  voluminous 
enlargement  of  the  withers  that  had  every  re- 
semblance of  the  fibrosis  of  fistula,  w^as  found 
after  an  unsuccessful  operation  to  be  affected 
with  a  very  large,  deeply  rooted  sarcoma  ex- 
tending downward  into  the  thorax  and  affect- 
ing nearly  the  whole  of  one  lung  in  addition  to 
involving  all  of  the  structures  about  the 
withers.  And  again,  the  author  once  submitted 
a  twelve-year-old  horse,  just  turning  white,  to 
an  operation  for  fistula  only  to  find  that  the 
bulging  was  due  to  a  melanotic  tumor  the  size 
of  a  cocoanut,  located  in  the  splenius. 

It  is  also  important  to  judge  carefidly  recent 
swellings  of  the  base  of  the  neck  and  of  the 
withers,  as  these  might  be  mistaken  for  fistula. 
Horses  frequently  sustain  severe  contusions  in 
this  region,  exhibiting  either  fluctuant  or  firm 


60  FISTULA  AND  POLL-EVIL 

swellings  that  are  not  easy  to  differentiate  from 
the  saccular  and  phlegmonous  conditions  as- 
sociated with  the  graver  state  preceding  the 
fistulous  stage.  Subcutaneous  and  subfascial 
sanguinous  sacs  and  hemotomata  complicated 
or  uncomplicated  with  infection,  are  the  mos^ 
misleading  of  these  lesions  for  which  fistulas 
might  be  mistaken.  The  differentiation  can 
never  be  made  with  certainty  until  the  behavior 
of  the  swelling  is  noted,  both  before  and  after 
evacuating  the  contents.  In  fistula  such  swell- 
ings accentuate;  in  the  others  they  subside, 
either  with  or  without  lancing.  Besides  they 
are  always  diffuse  whereas  the  fistulas  presents 
a  spherical  swelling  in  almost  every  instance. 

Although  acute  diseases  running  short 
courses,  malignant  edema  and  other  erysip- 
elatous inflammations  when  attacking  the 
withers  may  at  first  mislead  the  diagnostician, 
these  are  recognized  by  their  acuteness  and 
rapid  advancement  into  adjacent  regions  and 
the  serious  concomitant  toxemia. 

The  early  symptoms  of  the  atypical  form  are 
likewise  very  often  misleading.  That  any  given 
harness  sore  will  or  will  not  end  favorably  is 
not  always  easy  to  determine.  Wliat  might  at 
first  seem  like  a  simple  enough  harness  sore 
may  finally  prove  to  be  the  initial  phase  of  a 
bad  fistula.     On  the  other  liand,  a  badly  in- 


SYMPTOMS  61 

flamed  back  may  heal  promptly.  It  is,  there- 
fore, advisable  to  withhold  an  opinion  about 
the  seriousness  of  harness  sores  until  the  be- 
havior of  the  swelling  and  of  the  discharge 
can  be  noted.  As  a  rule,  however,  a  sore  that 
exposes  the  ligament,  and  especially  if  the 
pain  on  palpation  is  excruciating  and  extends 
along  the  back  some  distance  from  it,  is  one 
to  be  viewed  with  suspicion.  Painful  subacute 
diffuse  swellings  extending  forward  over  the 
summit  of  the  withers  are  likewise  incriminat- 
ing. Both  of  these  circumstances  indicate  an 
extensive  involvement  of  the  ligament  and  un- 
derlying bones  right  from  the  beginning  that 
is  pretty  sure  to  lead  to  a  chronic  inflammation 
of  these  structures  far  beyond  the  original 
focus — the  harness  sore. 

Sitfast  of  the  collar  seat,  on  the  contrary, 
develops  into  fistula  without  these  threatening 
external  manifestations,  and  even  without  any 
perceptible  pain.  It  causes  fistula  by  rooting 
through  the  connective  tissue  of  the  mane  into 
the  ligament  almost  unnoticed.  It  is  only  when 
sequestration  begins  or  when  extirpation  is 
attempted  that  the  depth  and  the  seriousness 
are  determined. 

During  this  first  stage  of  atypical  fistula — 
which  in  this  case  is  the  phlegmonous  stage — 
the  patient  is  not  stricken  with  illness  as  during 


62  FISTULA  AND  POLL-EVIL 

the  same  stage  of  the  typical  form.  The  trouble 
is  thus  far  more  like  simple  superficial  abscess 
and  is  not  attended  with  any  serious  toxemia. 
The  toxins  escape  through  the  wound,  whereas 
in  the  typical  form  they  are  pent  up  and  ab- 
sorbed. It  is  only  during  the  development  of 
secondary  abscesses  that  any  serious  systemic 
indisposition  is  ever  observed. 

The  syviptoms  of  the  fistulous  stage.  Fistula 
once  a  reality  and  beyond  the  developmental 
stage  produces  a  clinical  picture  well  known  to 
everyone  having  had  any  experience  with 
horses.  Its  exposition,  if  not  also  its  descrip- 
tion, might  seem  unnecessary  for  the  average 
reader,  so  well  known  are  the  manifestations 
of  this  fell  and  loathsome  disease. 

It  might  be  said  for  information  of  the 
novice  that  any  chronic  discharge  of  pus  from 
or  about  the  withers  is  fistula  of  the  withers. 
It  may  be  from  a  single  aperture  and  unas- 
sociated  with  swelling  or  it  may  be  from  two 
or  more  apertures  with  voluminous  enlarge- 
ment of  the  region  on  one  or  on  both  sides. 
The  apertures  may  be  located  posteriorh^  me- 
sially  or  anteriorly,  on  or  near  the  median  line 
or  laterally  at  any  point  about  the  neck  or 
shoulders.  The  most  anterior  location  at  which 
apertures  are  found  is  the  middle  cervical 
region  and  the  most  posterior  location  is  the 


SYMPTOMS  63 

acnestis.  These  two  extremes  are,  however, 
rare  ones.  Most  of  the  apertures  are  found  on 
or  about  the  level  of  the  withers  and  base  of  the 
neck.  Ventrally  pus  sometimes  burrows  sub- 
cutaneously  over  the  lateral  face  of  the  scapula 
and  points  at  the  level  of  the  shoulder  joint 
and  more  commonly  a  few  inches  above  that 
level.  The  amount  of  pus  discharged  varies 
with  the  size  of  the  cavity.  After  lancing, 
after  the  first  spontaneous  bursting  or  after  a 
secondary  abscess  has  been  evacuated  arti- 
ficially or  otherwise,  the  discharge  is  sometimes 
very  copious,  overrunning  the  sides  of  the  body 
as  far  down  as  the  foot  and  by  dessicating  en- 
crusts itself  thickly  over  the  whole  shoulder 
region  and  forearm.  The  discharge  finally 
moderates  and  may  even  cease  entirely  pend- 
ing the  formation  of  a  new  abscess  and  new 
aperture  often  on  the  opposite  side  or  at  some 
remote  location  on  the  same  side,  causing  the 
same  loathsome  condition  all  over  again. 

In  the  meantime  the  patient  loses  flesh  and 
is  unthrifty  in  general  appearance.  The  coat 
is  dull  and  uncouth,  the  ribs  and  skeletal  angles 
become  visible,  and  the  reduced  vitality  be- 
comes more  apparent.  It  is  only  the  patient 
that  is  well  groomed,  well  fed  and  well  attended 
as  to  its  infirmity  that  remains  in  good  con- 
dition.    The  neglected  subject  sinks  rapidly 


64  FISTULA  AND  PGLL-EVIL 

into  a  still  lower  state  of  depression  and  may 
even  die  from  chronic  septicema.  Operated  on 
in  this  enfeebled  state  fatalities  are  of  common 
occurrence. 

The  profile  of  the  withers  during  the  course 
of  the  fistulous  stage  varies  in  different  cases. 
Some  are  tumefied  on  one  side,  some  on  both, 
usually  from  fibrosis  but  also  from  common  in- 
flammatory swellings  which  subside  with  each 
pointing  of  the  abscess.  Each  aperture  leaves 
a  tell-tale  scar  and  a  denuded  zone  beneath 
where  the  discharges  have  destroyed  the  hair 
follicles.  Where  caustics,  strong  blisters  or 
strong  chemical  irrigations  have  been  em- 
ployed this  marring  is  still  more  pronounced 
(see  Fig.  4). 

Where  the  disease  was  left  to  run  its  own 
course,  or  was  treated  by  only  palliative  meas- 
ures, the  withers,  neck  and  shoulders  are  left 
riddled  with  these  indelible  blemishes,  and 
often  through  extensive  sloughing  of  the  liga- 
mentum  nuchge  the  neck  drops  down  in  front 
of  the  withers  into  a  permanent  deformity 
(ewe -neck). 

In  other  cases  the  spines  at  the  summit  of  the 
withers  having  lost  their  ligamentous  covering 
protrude  beneath  the  imperfectly  regenerated 
integument  and  thereafter  become  the  seat  of 
sores  from  the  harness  and  saddle  that  are  diffi- 


SYMPTOMS  65 

cult  to  heal.  At  the  sides  of  the  neck  just  in 
front  of  the  cephalic  angle  of  the  scapula  the 
permanently  enlarged  musculature  covered 
with  denuded  skin  likewise  chafes  from  the 
collar  and  thus  proves  a  constant  annoyance. 
JNIarred  and  sore-ridden,  the  subject  is  un- 
salable and  ofttimes  almost  useless. 


TREATMENT 

The  assertion  that  all  fistulas  of  the  withers 
might,  to  the  best  advantage,  be  submitted  to 
a  uniform  (standard)  method  of  treatment  is 
a  paradox.  It  is  a  paradox  because  such  a 
statement  at  first  thought  apparently  false  is 
after  all  entirely  true,  as  the  treatment  needs 
to  vary  only  in  regard  to  its  details.  The  same 
general  principles  of  management  and  treat- 
ment may  be  laid  down  for  all  of  them,  no 
matter  from  what  source  they  originate,  the 
course  they  may  have  taken,  or  the  stage  in 
which  they  are  found  when  submitted  for  the 
surgeon's  deliberation. 

That  certain  fistulge  of  the  withers  do  some- 
times yield  to  lateral  lancings  and  irrigations 
is  not  denied,  but  that  the  great  majority  surely 
but  slowly  develop  into  grave,  enfeebling,  in- 
curable and  often  fatal  afflictions  in  spite  of 
such  treatment  is  equally  true. 

It  is,  therefore,  evident  that  prompt  treat- 
ment of  the  radical  sort  is  indicated  at  an  early 
stage  and  before  the  infections  of  extraneous 
origin  have  done  a  widespread  damage  to  the 
ligaments,  bones  and  muscles,  and  before  pus 
has  burrowed  into  the  inaccessible  recesses  of 
this  complex  region. 


68  FISTULA  AND  POLL-EVIL 

It  does  not  matter  whether  the  condition  has 
been  caused  by  an  abrasion  or  has  originated  in 
li  cyst  of  the  dorsal  bursa,  procrastination  is 
inadvisable. 

We  have  found,  however,  in  the  cases  of  typi- 
cal fistulse  that  the  evacuation  of  the  contents 
of  the  sac  one  week  before  the  radical  operation 
is  performed,  is  good  practice,  because  it  forti- 
fies the  tissues  against  post-operative  infections 
of  a  grave  character.  Where  strict  aseptic  con- 
ditions are  maintained  in  the  operation  and 
the  patient  has  skillful  after-care,  this  precau- 
tion is  not  as  essential  as  when  careless  methods 
prevail  or  when  the  after-care  must  be  con- 
signed to  untrained  hands. 

It  is,  therefore,  recommended,  as  a  routine 
measure  in  field  practice,  to  lance  the  cyst, 
evacuate  the  liquid  and  flocculent  contents  and 
then  submit  the  sac  to  casual  irrigations  one 
week  to  ten  days  before  operating. 

In  the  case  of  old  fistulee  originating  as 
cysts  and  which  have  become  infected  from 
any  source  or  in  the  traumatic  variety  having 
either  superficial  or  deep  pus  accumulations, 
lancing  one  week  before  operating  is  likewise 
helpful  in  that  surgical  shock  is  modified  and 
there  is  less  soiling  of  the  surgical  wound  with 
pus  during  the  operation. 

These  suggestions  need  not  be  laid  down  as 


TREATMENT  69 

absolute  laws,  but  it  is  advisable  to  follow  them 
where  it  is  desired  to  take  advantage  of  every 
helpful  influence.  They  are  most  important 
in  subjects  enfeebled  from  hard  work  or  x)ri- 
vation  and  when  from  any  cause  a  clean  opera- 
tion and  good  after-care  cannot  be  carried  out. 

External  applications  such  as  liniments  and 
blisters  we  do  not  recommend.  They  only 
complicate  matters  by  irritating  the  skin  and 
encrusting  it  with  dried  excretions  difficult  to 
remove  in  preparing  the  field  for  operation 
later,  and  so  far  as  we  have  been  able  to  de- 
termine they  do  not  in  any  way  influence  the 
course  of  the  disease  within.  Occasional  cases 
abort  in  the  cystic  stage  but  this  trend  is  spon- 
taneous and  is  not  hastened  by  local  applica- 
tions, and  it  is  by  no  means  certain  that  the 
decrease  in  the  size  of  the  enlargement  is  per- 
manent. Our  observations  indicate  that  at 
least  some  of  these  rare  cases  recur  and  finally 
burst  to  the  surface. 

As  regards  the  application  of  caustic  chemi- 
cal substances  into  the  tracts  we  doubt  if  there 
is  any  charlatanry,  ancient,  medieval  or  mod- 
ern, that  savors  more  of  cruelty  and  malprac- 
tice. The  caustics — arsenic,  copper  sulphate, 
lye,  corrosive  sublimate,  caustic  lime,  zinc 
clilorid,  etc.,  after  dissolving  in  the  albuminous 
secretions   overflow  the  surface  of  the  bodv. 


70  FISTULA  AND  POLL-EVIL 

cause  severe  pain,  prolonged  discomfort  and 
permanent  blemish.  Often  large  patches  of 
integument  slough  away  ( Fig.  4 ) . 

The  only  beneficial  effect  of  caustics  is  the 
widening  of  the  aperture  and  tract  for  drain- 
age and  since  this  can  be  accomplished  better 
and  without  discomfort  by  other  means  the  one 
argument  in  their  favor  loses  force. 

The  treatment  of  fistula  of  the  withers  which 
in  our  hands  has  given  the  best  results  is 
prompt,  thorough,  surgical  intervention.  Our 
operation  of  choice  and  which  is  hereinafter  de- 
scribed consists  of  a  median  line  incision  ex- 
tending from  the  crest  of  the  withers  forwards 
six  to  twelve  inches  and  downward  through  the 
skin,  the  pad  of  the  mane  and  then  between  the 
two  halves  of  the  ligamentum  nuchas  into  the 
space  beneath  lying  over  the  summits  of  the 
second  and  third  thoracic  vertebrse.  This  is 
followed  by  a  resection  of  such  parts  of  the 
ligamentum  nuchge  as  are  thought  to  be  harm- 
ful and  then  by  making  lateral  drainage 
apertures  from  the  bottom  of  the  cavity  to  the 
surface  of  the  cervical  region  into  which  a 
perforated  drainage  tube  is  inserted. 

Radical  Operation  for  Fistula  of  the  Withers 

Prepai^ation. — As  the  procedure  is  one  of 
some  magnitude,  attended  with  all  of  the  dan- 


Fig.  4. — Effects  of  the  Use  of  Caustics. 
This  mule  was  treated   for  a  typica;!  fistula  of  the  withers 
by   the    injection    of    concentrated    lye.      Discharge    from   the 
wound  occasioned  sloughing  of  the  skin  over  large  areas. 


72  FISTULA  AND  POLL-EVIL 

gers  of  major  operations,  it  is  essential  to  in- 
vestigate carefully  into  the  patient's  physical 
condition.  Weak,  emaciated,  enfeebled  sub- 
jects should  be  given  a  preparatory  treatment 
that  will  tend  to  build  them  up  in  strength  and 
vigor.  This  may  consist  in  evacuating  and 
irrigating  large  abscesses,  cleaning  them  up 
over  the  soiled  shoulders,  grooming  the  body, 
good  feeding  and  any  general  good  care  that 
will  improve  the  health»  The  week  or  two  re- 
quired for  such  preparatory  treatment  is  not 
lost,  since  the  improved  health  before  the  op- 
eration will  shorten  the  duration  of  the  period 
of  post-operative  convalescence,  and  will  re- 
duce the  rate  of  mortality  which  in  enfeebled 
subjects  is  bound  to  be  high  on  account  of 
shock  and  the  magnitude  of  the  invading 
wound.  Large  wounds  cannot  be  made  in  the 
bodies  of  an  animal  with  impunity;  in  en- 
feebled subjects  they  are  positively  disastrous. 
Infections  run  riot  in  them  and  without  ef- 
fectual resistance  toxemias  are  fatal.  We, 
therefore,  advise  against  the  operation  in  sub- 
jects not  physically  fit  to  stand  the  ordeal. 

Dieting  is  also  essential  as  a  preparatory 
step,  as  no  animal  may  be  safely  cast  and  sub- 
mitted to  a  severe  surgical  operation  with  its 
alimentary  canal  filled  with  ingesta.  This  is 
especially  the  case  with  subjects  to  be  anesthe- 


TREATMENT  73 

tized,  with  chloroform  or  narcotized  with 
chloral. 

Preparation  of  the  Field. — Scraping  off  the 
dried  pus  encrusted  over  the  shoulders,  wash- 
ing the  skin  with  soap  and  hot  water  must  pre- 
cede the  attention  to  the  field  itself,  as  other- 
wise no  effectual  cleansing  of  the  withers  for 
surgical  work  would  be  effectual.  Preferably 
this  should  be  done  on  the  day  preceding  the 
oj^eration,  and  to  prevent  further  soiling  the 
shoulders  might  be  annointed  with  vaseline. 

The  hair  over  the  withers  and  on  each  side, 
down  no  less  than  ten  inches,  is  clipped  and  if 
possible  shaved.  The  mane  is  clipped  off  well 
forward  over  the  seat  of  the  collar  and  the  re- 
maining mane  is  braided  to  prevent  its  tufts 
from  dangling  into  the  wound  as  well  as  to 
keep  it  free  from  pus  during  the  after-treat- 
ment. 

A  good  ablution  with  brisk  friction  of  mer- 
curic chlorid  in  the  dilution  of  not  less  than  one 
part  to  fi\e  himdred  is  much  the  best  prepara- 
tory disinfection  of  the  skin  along  the  line  of 
incision.  The  field  might  in  addition  be 
painted  with  tinctin*e  of  iodin.  Shaving  the 
mane  hairs  especially  on  the  neck  where  the 
skin  is  folded  transversely  is  difficult  and  very 
tedious  as  the  folds  are  closed  while  the  liead  is 
erect  and  as  a  painstaking  shaving  process  pro- 


74  FISTULA  AND  POLL-EVIL 

longs  the  duration  of  decumbency  we  have  in 
our  recent  operations  been  satisfied  with  chp- 
ping.  By  using  the  curved  scissors  these 
coarse  hairs,  even  those  between  the  folds  can 
be  trimmed  away.  In  order  to  conserve  the  sub- 
ject's strength  by  shortening  the  duration  of 
the  operation  proper  it  is,  however,  preferable 
that  all  of  this  cleaning  up  process  and  disin- 
fection be  done  in  the  standing  position.  By 
standing  upon  an  elevation  in  a  place  where  the 
patient's  movements  can  be  controlled  and  by 
twitching  the  nose,  a  more  thorough  cleaning 
can  be  given  in  the  standing  position  than  after 
the  animal  has  been  cast.  When  the  body  lies 
flat  on  the  mat,  ground  or  even  the  operating 
table,  the  sides  of  the  withers  are  less  accessible 
for  clipping  and  washing,  and  besides  when 
this  is  postponed  until  the  subject  is  down,  the 
ground  under  and  about  the  withers  becomes  a 
disagreeable  place  to  occupy  while  operating. 

Anesthesia. — Chloroform  anesthesia  is  much 
the  best,  although  narcosis  with  chloral  hydrate 
administered  no  less  than  one  hour  before 
casting  will  answer  when  the  retinue  lacks  a 
satisfactory  anesthetist. 

For  this  purpose  we  administer  per  os,  pref- 
erably as  a  drench  twelve  drams  of  chloral 
dissolved  in  one  quart  of  warm  water.  Cannabis 
indica  intravenously,  chloral  in  the  peritoneal 


TREATMENT  75 

cavity  or  morphin  hypodermically  may  be 
substituted,  but  in  our  hands  these  agents  have 
been  greater  disappointments  as  surgical  nar- 
cotics than  chloral  hydrate,  which,  given  as 
above  described  on  an  empty  stomach,  always 
produces  some  measure  of  blunted  sensibility 
that  facilitates  the  control  of  the  patient  if  it 
does  nothing  more. 

When  chloroform  anesthesia  is  used,  every- 
thing is  made  ready  before  it  is  administered  in 
order  to  shorten  the  duration  of  unconscious- 
ness to  the  minimum. 

Restraint. — The  standing  position  even  with 
the  best  stocks  is  by  no  means  an  adequate 
restraint  for  effectual  work.  The  lunging  sub- 
ject is  in  danger  of  injury  and  the  movements 
of  the  neck  prevent  accuracy  of  technic.  The 
standing  position  answers  well  enough  for  lat- 
eral incisions,  such  as  may  be  required  to  evac- 
uate abscesses  preparatory  to  the  operation, 
but  when  the  center  of  the  withers  must  be  in- 
vaded for  the  purpose  of  resecting  a  necrotic 
ligament  or  of  perforating  the  cervical  muscles 
for  drainage,  the  control  must  be  complete — 
perfect. 

The  preferable  method  is  rope  restraint,  with 
all  fours  folded  securely  under  the  body.  The 
collar  part  of  the  rope  must  pass  from  breast 


76  FISTULA  AND  POLL-EVIL 

to  back  instead  of  encircling  the  neck.  The 
collar  seat  must  be  free  from  obstacles  because 
the  incision  crosses  it  and  besides  a  rope  en- 
circling the  base  of  the  neck  would  interfere 
with  making  the  lateral  apertures  for  drainage. 
A  rope  whose  collar  is  large  enough  to  drop 
under  the  sternum  while  its  backward  part  will 
rest  in  the  middle  of  the  back  is  best  adapted 
for  the  purj)ose,  as  it  leaves  the  withers  unob- 
structed. The  two  free  ends  of  the  rope  en- 
circle the  pasterns  of  the  hind  legs  and  then 
pass  forward  into  the  collar.  When  the  horse  is 
down  the  hind  legs  are  drawn  into  a  securely 
flexed  position.  The  fore  legs  are  tied  securely, 
flexed  with  straps  or  preferably  with  cords. 
Thus  secured  the  body  of  the  anesthetized  or 
narcotized  subject  can  be  rolled  into  the  ventral 
position  where  it  can  be  blocked  with  sacks  or 
held  by  several  assistants.  The  operator  stand- 
ing on  the  right  side  is  now  in  a  splendid  posi- 
tion to  proceed. 

On  the  operating  table  which  brings  the  body 
up  to  a  position  comfortable  enough  to  invade 
the  withers  mesially  there  is  the  objection  that 
the  under  side  is  not  very  accessible  for  making 
the  lateral  apertures.  Although  this  objection 
can  be  overcome  by  rolling  the  liead  and  neck 
downward  and  backward  there  is  by  no  means 
the  same  opportunity  to  perforate  the  cervical 


Fig.  5. — Tumor  forceps  of  a  serviceable  pattern  for  fistula 
operation.  The  style  of  the  jaws  in  tumor  forceps  is  a  mat- 
ter that  should  be  carefully  noted  in  purchasing  such  an  in- 
strument. For  instance,  some  vulsellum  forceps  are  so  de- 
signed that  the  incomplete  curve  of  the  jaws  together  with 
their  slender  and  weak  construction  makes  them  too  delicate 
for  much  veterinary  surgical  work.  The  instrument  illus- 
trated above  is  designed  so  that  with  them  a  firm  grasp  of 
tissues  is  possible  and  a  secure  hold  is  insured. 


Fig.  6. — Drainage  Tube  and  Inserter. 
By  means  of  the  drainage  tube  inserter  it  is  possible  to  in- 
troduce a  rubber  drainage  tube  with  a  minimum  of  invasion 
of  sound  tissue.  This,  in  many  cases,  is  an  important  fac- 
tor, as  it  prevents  needless  contamination  of  uninvaded  parts, 
limits  the  area  of  infected  tissue  and  possible  resultant  com- 
plications and  greatly  facilitates  the  execution  of  this  part  of 
the  technic.  Hemorrhage  is  reduced  to  a  minimum,  opera- 
tions are  completed  with  dispatch  and,  therefore,  with  less 
danger  of  surgical  shock  when  these  appliances  are  employed. 


78  FISTULA  AND  POLL-EVIL 

muscles  as  when  the  subject  is  tied  in  ropes  and 
rolled  into  the  ventral  position. 

histruments  Required. — A  good  strong  and 
well  sharpened  scalpel;  a  probe  pointed 
bistoury,  two  large  tumor  forceps,  an  assort- 
ment of  hemostats,  a  drainage  tube  inserter, 
a  perforated  rubber  drainage  hose,  a  large 
needle  threaded  with  strong  material.  There 
will  be  needed  in  addition  to  the  usual  basins 
for  antiseptics,  a  separate  basin  containing  an 
abundance  of  oakum,  which  is  to  be  used  for 
packing  the  cavity  immediately  after  the  op- 
eration has  been  completed.  We  use  clean 
oakum  soaked  in  a  strong  solution  of  mercuric 
chlorid  for  this  purpose  and  with  this  we  place 
the  threaded  needle  to  prevent  its  thread  from 
becoming  entangled  among  the  instruments 
while  operating. 

A  yard  of  muslin  or  burlap  will  also  be 
needed  to  cover  the  withers  as  a  protection 
against  soiling  after  the  patient  is  returned  to 
the  stable. 

Tech7iic. — Standing  on  the  side  of  the 
patient  now  rolled  in  the  ventral  position, 
facing  toward  its  head,  the  operator  plunges 
the  scalpel  deeply  into  the  middle  of  the  neck 
at  a  point  varying  from  six  inches  to  twelve 
inches  in  front  of  the  crest  of  the  withers,  and 
then  draws  it  backward  as  far  as  the  crest — the 


TREATMENT  79 

full  depth  of  the  blade.  The  variation  in  length 
of  the  incision  is  necessitated  by  the  difference 
in  the  size  of  the  patient,  in  the  thickness  of 
the  skin  and  underlying  pad,  and  also  by  the 
size  of  the  tumefaction.  In  a  small  horse,  for 
example,  having  only  a  small  rounded  sac 
bulging  at  one  side,  an  incision  six  inches  long 
will  be  found  ample,  while  in  a  large  "meaty- 
necked"  draft  horse  having  an  enormous  swell- 
ing it  must  be  at  least  twelve  inches  long. 
Otherwise  the  walls  of  the  wound  cannot  be 
parted  enough  to  give  a  good  access  to  the  bot- 
tom of  the  cavity  for  inspection  and  for  resec- 
tion of  diseased  parts  of  the  ligament.  We 
aim  in  the  first  stroke  of  the  knife  to  incise 
the  skin  and  underlying  pad  from  end  to  end, 
that  is,  from  the  point  decided  upon  anteriorly 
to  the  crest  of  the  withers.  For  descriptive 
purposes  this  may  be  designated  the  first  step 
of  the  operation. 

In  the  second  step  each  of  the  edges  of  this 
large  wound  is  grasped  deeply  with  the  tumor 
forceps.  An  assistant  should  hold  one  of  the 
forceps  and  the  operator  the  other  By  draw- 
ing the  wound  apart  with  some  force  the  bleed- 
ing now  spurting  from  many  small  vessels  is 
immediately  controlled  and  after  Avidening  it 
out,  a  good  view^  of  the  bottom  is  obtained  for 
the  next  incision.    The  scalpel  is  now  plunged 


80  FISTULA  AND  POLL-EVIL 

between  the  two  halves  of  the  funniciilar  por- 
tion of  the  hgamentum  nuchge  into  the  loose 
tissue  beneath  and  drawn  backward  again  the 
full  length  of  the  wound.  This  opens  the  cen- 
tral cavity  which  in  typical  fixtula^  is  uni- 
formly located  at  the  level  of  the  second  tho- 
racic spine. 

The  third  step.  Blood  is  now  hurriedly  wiped 
out,  the  forceps  are  drawn  upon  with  force  to 
reduce  the  flow  and  the  large  spurters  are 
snapped  up  in  hemostats.  It  is  not,  however, 
advisable  to  devote  much  time  to  this  hemo- 
stasia unless  efforts  at  its  control  promise  to  be 
promptly  effectual,  since  futile  attemj)ts  de- 
lay the  work  and  add  to  the  blood  loss.  If  the 
operation  antedates  the  formation  of  pus,  that 
is,  if  the  contents  are  still  sero-fibrinous,  there 
is  no  occasion  for  doing  anything  else  than  that 
of  now  inserting  the  drainage  tube,  while  on 
the  other  hand,  if  there  is  pus  and  the  ligament 
is  found  more  or  less  riddled  with  disease,  re- 
section of  the  diseased  parts  is  now  under- 
taken. In  very  old  cases  it  is  entirely  removed, 
in  more  recent  cases  its  mesial  parts  are  sliced 
off.  In  this  step  we  also  in  many  cases  en- 
deavor to  resect  the  wall  of  the  sac,  or  as  mucli 
of  it  as  is  accessible  for  hurried  removal,  leav- 
ing the  ligament  imtouched.  This,  of  course, 
is  possible  only  where  the  sac  is  small  and  on 


TREATMENT  81 

account  of  age  has  a  well  defined  limiting  wall. 
It  is  often  possible  in  many  cases  to  resect  the 
sac  and  then  heal  up  the  wound  under  aseptic 
conditions  without  drainage.  More  often, 
however,  the  region  is  invaded  with  infection 
of  long  duration  and  exhibits  necrotic  areas 
which  must  be  removed.  For  example,  if  the 
ligament  is  found  carpeted  with  undulated 
granulations  and  is  seen  to  exhibit  necrotic 
spots  or  is  riddled  with  pus  tracts,  it  should  be 
entirely  removed  The  resection  is  effected  by 
cutting  it  off  anteriorly,  grasping  the  end  with 
a  tumor  forceps  and  then  dissecting  it  in  the 
backward  direction  to  the  posterior  commis- 
sure of  the  wound.  This  is  done  on  both  sides 
or  only  on  one  side  according  to  the  condition 
in  which  the  ligament  is  found.  When  not  too 
firmly  fixed  into  the  adjacent  connecting  tis- 
sue it  can  often  be  torn  out  with  the  tumor 
forceps. 

The  bones  beneath  are  left  severely  alone. 
Trimming  with  bone  forceps  or  curette  is  not 
recommended.  Spontaneous  exfoliation  is  de- 
pended upon  exclusively.  We  have  found  that 
meddling  with  the  spinous  processes  is  a  harm- 
ful practice.  The  exposed  curetted  ends  be- 
come open  channels  for  the  descent  of  new  and 
deeper  inflammatory  processes,  when  later  dur- 
ing the  healing  they  are  constantly  soaked  in 


82  FISTULA  AND  POLL-EVIL 

pus.  Necrotic  ends  sooner  or  later,  without  in- 
terference, separate  from  the  viable  bone,  and 
then  leave  it  carpeted  with  granulations  which 
now  cicatrize  with  the  rest  of  the  wound.  We 
are,  therefore,  unequivocally  opposed  to  the 
removal  of  bone  tissue  other  than  the  already 
welMoosened  sequestra,  which  are  sometimes 
Found  floating  in  the  cavity  or  feebly  attached 
in  situ. 

The  fourth  step  is  the  insertion  of  the  drain- 
age tube.  This  is  done  with  the  drainage  tube 
inserter.     (Fig.  3.) 

Armed  with  the  tube  the  point  of  the  inserter 
is  placed  at  the  bottom  of  the  cavity  and  then 
pushed  out  laterally  in  the  downward  direction 
through  the  splenius  and  serratus  cervicis  mus- 
cles to  the  surface.  The  skin  must  be  incised 
as  the  j)oint  of  the  inserter  bulges  it  out  as  its 
point  is  not  sharp  enough  to  penetrate  it  un- 
assisted by  an  incision.  When  inserted  on  the 
one  side  the  inserter  is  passed  into  the  other 
end  of  the  tube  and  pushed  through  the  same 
place  on  the  opposite  side.  This  places  the 
tube  across  the  bottom  of  the  cavity  and  out  to 
each  side  of  the  neck.     (Fig.  4.) 

When  the  operation  is  prolonged  for  any 
cause  and  the  blood  loss  has  been  great,  we 
postpone  the  insertion  of  the  tube  until  the 


TREATMENT 


second  day,  at  which  time  it  is  inserted  in  the 
standing  position. 

It  is  advisable  in  passing  tubes  through  this 
thick  musculature  to  keep  the  neck  in  a  nor- 


Inserting  the  Drainage  Tube. 


mal  position.     Otherwise  the  tube  will  be  in  a 
strained  position. 

The  fifth  step  is  that  of  packing  and  sutur- 
ing the  cavity.  For  this  we  use  sterilized  anti- 
septic oakum.    We  prepare  the  oakum  already 


84  FISTULA  AND  POLL-EVIL 

arranged  in  wads  of  different  sizes  so  that  it 
can  be  packed  into  the  recesses  piece  by  piece 
where  it  will  press  directly  upon  the  bleeding 
vessels  and  thus  arrest  the  hemorrhage  at  once. 
If  indifference  is  displayed  in  this  connection, 
the  bleeding  may  force  its  way  between  the 


Fig.  8. — The  Drainage  Tube  Inserted. 
This  shows  the  position  of  the  drainage  tube  in  an  atypical 
case  of  fistula  before  the  would  is  sutured.     In  typical  fistula 
the  tube  would  be  inserted  more  anterior,  making  its  exit  at 
the  point  marked  X. 

layers  of  the  surrounding  tissues.  Once  well 
packed  the  wound  is  closed  with  sutures  deeply 
inserted  into  each  lip.  The  wound  must  be 
closed  tight  to  prevent  any  further  blood  loss. 
Dressmg.  When  the  patient  rises  to  its  feet, 
its  body  is  washed  free  of  all  blood  accumula- 


TREATMENT  85 

tions,  and  rubbed  as  dry  as  possible.  We  then 
cover  the  withers  with  a  layer  of  cotton  or 
gauze  and  hold  it  in  place  with  a  muslin  or  bur- 
lajD  sheet  tied  down  with  cords  encircling  the 
breast  and  the  girth.  Tlie  patient  is  now  ready 
for  the  stall. 

After-care.  At  the  end  of  twenty- four  hours 


Fig.  9. — The  Drainage  Tube  After  the  Wound  Has  Been 
Sutured,  Typical  Fistula. 

the  sutures  are  removed  and  the  packing  lifted 
out  carefully.  There  is  at  this  time  still  some, 
danger  of  bleeding  if  the  interior  of  the  cavity 
is  harshly  handled.  We,  therefore,  advise  that 
no  attempt  be  made  to  clean  out  the  blood  clots 
attached  here  and  there  about  the  cavity  until 
the  end  of  forty-eight  hours,  but  that  we  con- 
tent ourselves  with  a  second  packing  of  oakum 


S6  FISTULA  AND  POLL-EVIL 

or  gauze  soaked  in  mercuric  chlorid  solution 
and  bound  down  with  the  withers  bandage.  At 
the  end  of  forty-eight  hours  we  give  the  whole 
cavity  a  good  cleaning  under  strict  aseptic  pre- 
cautions, removing  the  blood  clots  attached  to 
the  tissue  completely.  The  cavity  is  now 
sprinkled  with  iodoform  and  then  filled  up  with 


Fig.  10. — The  Drainage  Tube  After  the  Wound  Has  Been 
Sutured,  Atypical  Fistula. 

a  mixture  consisting  of  iodoform  five  per  cent 
and  boric  acid  ninety-five  per  cent  and  the 
withers  protected  again  with  clean  cotton  and 
the  bandage. 

In  cases  where  the  wound  has  not  been  soiled 
during  the  operation  a  daily  renewal  of  the 
antiseptic  powder  after  wiping  out  the  old  will 


TREATMENT  87 

answer  for  the  after-care,  but  where  the  cavity 
was  found  badly  infected  or  in  instances  where 
the  operation  was  not  a  perfectly  clean  one,  it 
is  essential  that  the  powder  be  renewed  no  less 
frequently  than  three  times  a  day  for  the  first 
four  days.  By  attending  with  great  care  to 
this  large  wound,  the  discharges  will  not  be 
abundant,  but  when  the  whole  area  of  exposed 
flesh  is  allowed  to  become  contaminated  the  is- 
sue is  copious.  It  is,  therefore,  important  to 
pay  strict  attention  to  the  wound,  treating  it 
skillfully  during  the  first  four  days.  After 
four  days  there  is  less  danger  of  grave  infec- 
tions gaining  any  headway  in  the  wound  as 
the  tissues  are  then  better  protected  against 
microbian  invasion. 

The  drainage  tube  is  managed  much  like  a 
seton.  We  fasten  a  spike  across  one  end  and 
then  pull  it  through  from  the  other  end  and 
give  the  holes  and  lumen  a  good  cleaning.  A 
stylet  is  needed  to  dislodge  the  dried  pus  that 
chokes  it.  By  bending  it  about,  cleaning  its 
holes  and  ramming  a  stylet  through  its  lumen 
and  then  rinsing  it  well  with  a  strong  antisep- 
tic solution,  it  can  be  kept  perfectly  clean  and 
open.  The  next  day  the  same  manner  of  hand- 
ling is  repeated  except  that  it  is  draw^n  to  the 
opposite  side. 

Cases  having  an  osseous  comjilication  should 


88  FISTULA  AND  POLL-EVIL 

be  watched  more  carefully.  They  must  not  be 
allowed  to  close  above  before  sequestration  is 
complete  and  the  bone  is  in  condition  to  cica- 
trize with  the  rest  of  the  wound.  It  is  here 
that  recurrences  occur.  Stumps  of  bare  verte- 
brjE  are  covered  by  scar  tissvie  and  cause  a  re- 
accumulation  of  pus  which  will  require  subse- 
quent attention  if  not  a  second  operation  of 
equal  magnitude. 

During  the  healing  of  the  wound  its  walls 
are  scrutinized  daily  for  shreds  of  ligament 
that  are  becoming  surrounded  with  granula- 
tions before  detaching  from  their  viable  con- 
tinuation. It  often  happens  that  large  sloughs 
of  ligamentous  or  new-formed  fibrous  tissue 
appear  here  and  there  about  the  cavity  as  cica- 
trization proceeds.  These  delay  healing  and 
should  be  removed  as  soon  as  possible. 

At  the  end  of  five  weeks  we  usually  dispense 
with  the  tube  and  apply  such  simple  astring- 
ents as  a  two  per  cent  solution  of  zinc  sul- 
phate or  common  white  lotion.  At  this  time 
horses  may  be  worked  with  breast  harness 
but  collar  pressure  directly  upon  the  region  is 
not  admissible  until  after  three  months  have 
elapsed. 

Modifications 

Large  subcutaneous  or  subfascial  abscesses 
are  evacuated  at  dependent  points  and  drain- 


TREATMENT  89 

age  apertures  maintained  as  long  as  there  is 
any  issue  from  them.  When  the  discharge 
continues  to  be  profuse,  attempt  should  be 
made  to  locate  the  cause.  The  main  cavity  has 
not  been  drained.  If  located  in  an  inaccessible 
place,  as  for  example  upon  the  cervical  verte- 
brae (cervical  fistula)  or  along  the  thoracic 
vertebra  under  the  longissimus  dorsi,  spinalis 
or  complexus,  it  may  not  be  possible  to  give 
helpful  assistance.  These  secondary  abscesses 
are  the  result  of  improper  treatment  or  neglect. 
They  seldom  if  ever  complicate  a  well  directed 
operation  followed  by  faithful  after-care. 

In  the  case  of  atypical  fistula  arising  from 
wounds  of  the  back  or  crest,  the  operation  is 
much  the  same  except  that  the  incision  is  made 
more  posteriorly  (Fig.  10). 

It  is,  however,  never  advisable  to  make  such 
a  median  line  incision  on  a  thin  horse  having  a 
prominent,  sharp  withers,  as  the  w^ound  lips 
will  sag  down  below  the  level  of  the  vertebra? 
and  produce  a  condition  that  will  heal  very 
slowly  and  imperfectly.  In  draft  horses  with 
thick,  low  withers  there  is  less  danger  from  this 
standpoint.  The  fleshy  surrounding  affords 
ample  protection  against  protrusion  of  the 
crest  above  the  level  of  the  wound  edges. 


90  FISTULA  AND  POLL-EVIL 

Special  Remarks 

Objections  have  been  raised  against  the  use 
of  drainage  tubes  in  the  treatment  of  fistula 
on  the  grounds  that  they  are  difficult  to  keep 
open.  This  objection  we  are  sure  comes  from 
those  who  have  not  persevered  in  their  use.  A 
tube  long  enough  to  cross  the  neck  and  pro- 
trude no  less  than  eight  inches  on  each  side  is 
very  easily  cleaned  without  removing  it  en- 
tirely, as  described  above,  and  after  it  has  es- 
tablished a  good  tract  for  itself  it  can  be  taken 
out  entirely  for  cleaning  and  can  be  easily  rein- 
serted. It  is  essential  that  a  tube  be  composed 
of  strong  material,  strong  enough  to  resist  the 
pressure  upon  it.  It  must  not  collapse.  A 
soft  tube  is  worthless.  When  the  strong  mus- 
cles through  which  it  passes  press  upon  it,  its 
usefulness  for  drainage  is  destroyed.  We, 
therefore,  recommend  a  stong  reinforced  rub- 
ber hose  which  we  perforate  with  a  harness 
punch  (Fig.  6.) 

To  prevent  drainage  tubes  from  coming  out 
we  arm  each  end  with  a  common  twenty  penny 
nail  passed  across  at  right  angles.  A  meat 
skewer  or  common  round  stick  will  also  answer 
the  same  purpose. 

It  seems  important  to  emphasize  here  the 
worthlessness  of  mere  incisions  through  thick 
muscles  as  drainage  apertures.     A  collaj)sed 


TREATMENT  91 

aperture  through  muscle  tissue  does  not  drain 
in  the  surgical  sense.  Such  an  aperture  leaks 
pus  but  does  not  drain  the  cavity  dry  enougli 
to  serve  the  purpose  for  which  drainage  is 
needed.  It  does  not  matter  how  many  drain- 
age incisions  are  made  through  muscle  tissue, 
the  cavitv  would  still  overflow  unless  the  aper- 
tures are  held  wide  open  with  a  tube.  The 
same  may  be  said  of  setons.  While  pus  is  ab- 
sorbed by  them  (in  very  limited  quantities) 
they  do  not  empty  the  cavity  and  are,  there- 
fore, worthless.  To  heal  a  wound  as  large  as 
the  one  required  to  expose  the  diseased  part  of 
a  fistula  of  the  w^ithers,  it  is  essential  that  it  be 
kept  free  from  accumulations  of  its  secretions. 

Accidents  and  Sequelae 

Septicemia  is  the  commonest  sequel  of  the 
operation.  It  is  predisposed  by  enfeebled 
states  of  the  patients  but  can  often  be  traced 
to  badly  directed  surgical  work.  Failure  to 
obey  the  common  laws  of  modern  surgery  as 
regards  asepsis  is  always  disastrous  in  opera- 
tions of  this  magnitude,  and  since  this  one  is 
performed  often  in  a  pus  ridden  region,  dirty 
internally  and  externally,  and  must  often  be 
done  where  conditions  are  none  too  favorable, 
the  operation  exacts  its  full  toll  of  fatality 


92  FISTULA  AND  POLL-EVIL 

from  septicemia,  even  in  the  most  vigorous  sub- 
jects. 

The  prevention  hes  in  making  the  best  of 
the  situation  by  using  sterihzed  instruments, 
cleaning  the  hands  well,  packing  the  wound 
with  a  safe  wadding  and  then  protecting  it 
thereafter  until  the  danger  of  a  grave  infection 
has  passed.  It  is  also  very  essential  to  remove 
the  packing  material  at  the  end  of  twenty- four 
hours  so  that  the  blood  supply  of  the  tissues 
pressed  upon  by  the  tight  packing  will  be  re- 
stored to  the  walls  of  the  wound.  A  packing 
of  doubtful  purity  wadded  tightly  into  a 
wound  as  large  as  this  one  is  indeed  a  hazard. 
It  weakens  the  tissues  and  besides  impregnates 
them  with  infections. 

Malignant  Edema 

We  have  had  cases  of  malignant  edema  fol- 
low operations  where  the  directions  given  about 
the  removal  of  the  packing  were  not  carried 
out.  To  let  a  packing  sojourn  forty-eight 
hours  in  a  large  wound  always  invites  anaer- 
obic infections  of  this  character.  In  fistula  of 
the  withers  it  is  positively  disastrous.  There 
is  danger  from  this  disease  even  after  appar- 
ently clean  operations  because  the  condition 
created  is  so  favorable.  The  prompt  removal 
of  the  packing  at  the  end  of  twenty- four  hours 


TREATMENT  93 

and  the  re-application  of  a  well  soaked  anti- 
septic pack  is  universally  preventive. 

Hemorrhage 

The  hlood  loss,  always  considerable,  often 
reaches  the  danger  point  when  large  radicals 
of  the  nutrient  arteries  are  divided  and  the  clos- 
ing up  of  the  wound  is  in  some  way  delayed. 
We  depend  more  upon  hasty  work  and  prompt 
closure  of  the  cavity  to  limit  the  blood  loss 
than  upon  ligation  or  forcep  hemostasia.  Often 
when  blood  is  gushing  from  some  part  of  the 
wound  in  a  threatening  manner  and  a  forcep 
cannot  be  snapped  upon  it  promptly  we  pack 
the  bleeding  place  with  a  hard  wad  of  oakum 
and  let  an  assistant  hold  it  down  tight  with  a 
long  blunt  instrument  while  the  work  proceeds 
without  further  hindrance.  While  cognizant 
of  the  fact  that  this  is  not  a  display  of  the  best 
surgery,  it  has  always  seemed  impossible  for 
us  to  make  any  headway  in  the  direction  of  sys- 
tematic hemostasia  in  these  operations  and  we 
have  come  to  the  conclusion  that  less  blood  is 
lost  by  hurrying  through  the  work  and  then 
depending  upon  the  packing  to  prevent  any 
further  loss. 

In  exceptionally  large  withers,  infiltrated 
with  an  abundance  of  newly  formed  fibrous  tis- 
sue, the  woimd  is  of  such  magnitude  that  in 


94  FISTULA  AND  POLL-EVIL 

spite  of  care  the  loss  of  blood  assumes  danger- 
ous proportions.  And  while  fatahties  from 
this  cause  are  not  usual,  the  weakened  state 
produced  by  excessive  bleeding  operates  with 
other  influences  against  the  general  welfare  of 
the  patient  during  the  first  few  days  of  con- 
valescence. 

Recurrence 

When  the  withers  tumefy  again  after  the 
wound  has  been  healed  for  some  time  or  when 
it  does  not  heal  in  the  usual  time,  it  is  evident 
that  some  necrotic  ligament  or  bone  still  re- 
mains. These  may  have  been  overlooked  in  the 
operation  or  else  the  disease  may  have  ad- 
vanced into  adjacent  places.  We  have  found 
that  most  of  oiu*  recurrences  are  due  to  healing 
of  the  wound  before  the  spines  have  cast  off  the 
sequestra.  A  second  operation  of  lesser  mag- 
nitude often  reveals  a  loosened  segment  which 
on  removal  is  followed  by  j^rompt  cicatrization. 
When  this  is  not  found  to  be  the  cause  a  new 
operation  tlie  same  as  the  first  may  be  required. 

Complications 

The  complications  arising  from  fistula  of  the 
withers  independent  of  those  caused  entirely 
by  operations  and  other  remedial  measured 
M'hicli  will  be  considered  under  the  head  of  "se- 


TREATMENT  95 

quels  and  accident"  are:  Acute  septicemia, 
chronic  septicemia,  pneumonia,  pleurisy  and 
paralysis. 

1.  Septicemia.  As  already  mentioned  under 
the  chapter  on  pathogenesis,  there  is  a  toxemia 
associated  with  every  case  of  fistula.    The  only 
exception  is  during  the  saccular  stage  of  the 
typical  form.    After  infection  has  entered,  the 
situation  is  only  a  question  of  how  badly  the 
patient  is  affected  by  this  complication.    Some 
patients  resist  this  systemic  complication  bet- 
ter than  others,  but  after  a  fistula  has  become 
chronic  and  has  drained  the  patient's  vitality 
by  copious  discharges  of  pus  for  a  long  while, 
impregation  of  the  organism  with  toxic  prod- 
ucts and  bacteria  occurs  to  a  greater  or  less 
extent  in  every  case.    Death  from  acute  sep- 
ticemia, except  after  operations,  is  rare,  but 
clinical  chronic  septicemia  is  a  very  common 
occurrence.     It  is  this  complication  that  most 
undermines  the  health  of  all  cases  and  which 
causes  the  emaciation  and  general  enfeeble- 
ment  already  referred  to.   And  while  the  com- 
plication   is    an    insidious    one,    deaths    occur 
therefrom  quite  often.     We  have  found  sec- 
ondary abscess  of  the  lungs  and  of  tlie  spleen 
in  animals  that  have  died  from  fistula.    As  a 
source  of  focal  infection  fistulse  of  the  with- 


96 


FISTULA  AND  POLL-EVIL 


ers  is  by  far  the  best  example  we  have  in 
domestic  animal  pathology.  Its  symptoms  are 
seen  in  the  unthrifty  and  enfeebled  state  of 
the  patient  and  in  its  susceptibility  to  other 
diseases,  particularly  to  new  infections  after 


Fig.    11. — A    Complicated   Case   of   Fistula   and    Poll-Evil. 

operations,  and  to   pneumonia — the   common 
form  of  dissolution  of  so  many  diseases. 

Pneumonia 

The  pneumonia  arising  as  a  complication  of 
fistula  of  the  withers  occurs  chiefly  in  old  debil- 
itated subjects  or  in  younger  animals  reduced 
to  a  state  of  general  enf eeblement  from  neglect 
and  exposure.  It  is  sometimes  also  metastatic- 
abscess  of  the  lungs — the  infection  is  carried 
^from  the  purulent  hot  bed  to  the  pulmonary 


TREATMENT  97 

capillaries  where  the  lung  tissue  falls  an  easy 
prey  to  the  subsequent  pyogenesis.  We  have 
found  the  lungs  riddled  with  abscesses  in  af- 
fected horses  that  have  died  from  fistula. 

Pleurisy 

The  pleura  is  occasionally  attacked  with  an 
inflammatory  process  arising  from  its  conti- 
nuity with  the  affected  musculature  sin-round- 
ing it.  The  deep  secondary  abscesses  which 
burrow  down  to  the  bodies  of  the  vertebra^  and 
then  descend  over  the  costal  surface  are  the  in- 
fluential factors  in  this  connection.  At  first  cir- 
cumscribed, the  inflammation  soon  extends  over 
a  wider  surface  until  the  subject  is  affected  with 
a  diffuse  fatal  sero-fibrinous  pleuritis.  Figure 
11  illustrates  a  case  affected  both  with  poll-evil 
and  fistulee  of  the  withers.  The  subject  was 
seven  years  and  a  fair  type  of  delivery  wagon 
horse  weighing  eleven  hundred  and  fifty 
pounds.  It  was  first  attacked  with  poll-evil, 
but  before  this  was  submitted  for  treatment 
the  withers  were  already  tumefied  with  a 
phlegmonous  enlargement.  The  poll-evil  was 
submitted  to  the  radical  operation  and 
promptly  cured  after  thirty  days.  During  this 
period  of  convalescence  from  the  poll-evil  oper- 
ation, the  withers  pointed  and  discliarged  a 
copious  quantity  of  pus  on  the  right  side  ad- 


98  FISTULA  AND  POLL-EVIL 

jacent  to  the  cervical  angle  of  the  scapula.  The 
patient  was  not  relieved  from  this  evacuation 
but  on  the  contrary  remained  indisposed,  re- 
fusing to  move  about  except  when  urged,  and 
at  each  movement  grunted  with  agony.  The 
respirations  at  first  only  slightly  accelerated 
became  gradually  faster  during  the  succeeding 
three  weeks,  at  which  time  several  gallons  of 
exudate  were  aspirated  from  the  right  side  of 
the  thorax.  The  patient's  condition  became 
gradually  worse  and  at  six  weeks  following  the 
evacuation  of  the  withers  it  died  from  a  re- 
filling of  the  pleural  sacs.  The  post  mortem 
examination  of  the  carcass  showed  clearly  a 
case  of  pleurisy  beginning  along  the  dorsal  re- 
gion extending  with  a  gradual  lessening  in- 
tensity in  the  downward  direction  over  the 
thoracic  parietes,  beginning  at  the  intercostal 
lymph  nodes,  which  were  found  enlarged. 

Paralysis 

Nervous  involvement  is  less  likely  to  com- 
plicate fistula  of  the  withers  than  poll-evil,  be- 
cause the  spinal  cord  of  the  dorsal  region  is 
better  protected  against  encroachment  from 
extending  pyogenic  processes.  We  have  never- 
theless  observed  cases  in  which  death  due  to 
spiTvitis  arising  from  extension  of  the 
disease  into  the  neural  canal.    The  patients  al- 


TREATMENT 


99 


ready  weakened  from  the  disease  and  also  from 
general  neglect  weakened  in  the  hind  quarters 
and  after  exhibiting  a  progressive  paralytic 
state,  were  finally  found  unable  to  rise,  dying 
in  delirium  after  some  days  of  decumbency. 


Fig.  12. — Cold  Abscess  of  the  Prescapular  Lymph   Nodes. 
Following  Fistula  of  the  Withers. 

Cold  Abscess  of  the  Prescapular  Lymph  Nodes 

The  adjacent  lymph  nodes  may  suppurate 
during  or  following  fistula  of  the  withers  as 
shown  in  case  of  a  draft  horse  (Fig.  14) .  After 
recovering  from  an  operation  for  a  fistula  of 
the  withers  and  before  having  been  put  to 
work  a  pronounced  enlargement  developed  at 


100  FISTULA  AND  POLL-EVIL 

the  shoulder.    This  proved  to  be  a  typical  cold 
abscess  involving  these  lymph  nodes. 

Fistula  Caused  From  Collar  Sitfasts 

There  is  a  type  of  fistula  that  differs  some- 
what from  those  just  described.  It  is  located 
in  front  of  the  generally  accepted  limits  of  the 
withers  proper,  and  it  exhibits  certain  etiologic, 
pathologic  and  clinical  differences  that  call  foi 
a  special  description  and  which  require  differ- 
ent methods  of  management. 

This  injury  starts  as  a  cutaneous  collar  le- 
sion. It  begins  as  a  pressiu*e  necrosis  of  the 
skin  alone  but  later  involves  first  the  pad  of  the 
mane  and  then  the  funicular  portion  of  the 
ligamentum  nucha?  and  even  extends  down- 
ward into  the  lamellar  portion,  creating  a  very 
troublesome  condition  to  treat. 

When  observed  in  the  early  stage  of  devel 
opment,  the  seat  of  the  collar  at  the  level  of 
the  mane  where  the  thick  skin  is  folded  trans- 
versely into  several  deep  undulations,  is  found 
to  contain  a  black,  smooth,  hairless^  leather- 
like, circular  zone  of  insensitive  integument 
that  is  loosened  slightly  from  the  viable  skin 
all  ai'ound  its  circumference,  but  which  can  not 
be  lifted  off.  It  is  attached  and  although  some 
time  is  given  for  it  to  separate,  no  such  an  event 
occurs.     It  remains  stubbornly  attached.     At 


TREATMENT  101 

first  there  is  no  swelling  and  the  patient  dis- 
plays little  discomfort,  but  later  when  the  dead 
tissues  begin  to  putrefy  and  impregnate  the 
adjacent  tissues  with  infections  or  serve  as  an 
avenue  of  entrance  into  them,  the  subject  be- 
comes unfit  to  work  with  a  collar,  a  certain 
amount  of  discharge  begins  to  appear  around 
its  borders,  and  the  subjacent  musculature  be- 
comes swollen  or  bulges  from  the  swollen  lig- 
aments within.  Soon  the  slough  which  is  a  large 
cone-shaped  mass  of  skin  and  pad  detaches 
itself  and  can  then  be  removed  by  blunt  dis- 
section, leaving  a  deep  well  whose  bottom  is 
the  ligamentum  nuchge.  Treated  as  an  open 
wound  the  cavity  often  closes  up  with  nothing 
more  harmful  than  a  slight  deformity  of  the 
neck  which  will  vary  according  to  the  size  of 
the  slough  removed. 

Many  cases,  however,  do  not  behave  so  well. 
Cicatrization  of  the  cavity  leaves  a  small  fistu- 
lous tract  that  runs  down  to  and  often  under 
the  ligamentum  nuch^e,  and  w^hich  in  spite  of 
local  treatment  continues  to  discharge  consid- 
erable ])us.  The  sides  of  the  neck  along  the 
ligament  bulge  slightly  in  both  the  forward  and 
the  downward  directions.  This  Ls  fistula  from 
sitfast.  Later  if  no  relief  is  given  the  lamellar 
portion  becomes  involved,  at  first  only  slightly 
but  later  over  a  wider  and  wider  zone  until  the 


102  FISTULA  AND  POLL-EVIL 

whole  lower  third  of  the  cervical  region  is  hard 
and  tumefied.    Abscesses  may  point  well  for- 
ward along  the  neck  and  as  far  down  as  the 
level  of  tlie  vertebrge.     This  is  cervical  fistula, 
a  type  that  may  also  result  from  either  the  typ- 
ical or  the  atypical  types  previously  described. 
The  treatment  of  fistula  from  sitfast  should 
begin  with  prevention.    That  is  to  say,  the  sit- 
fast  should  be  properly  managed.     It  is  an 
error  to   allow  even  the  smallest   superficial 
sitfast  to  sojourn  on  the  neck  unchecked.    The 
veterinarian  should  recommend  prompt  extir- 
pation and  give  warning  about  the  serious  state 
that   may    develop    from    careless    treatment 
thereafter.    The  sitfast  should   be   extirpated 
down  into  the  sound,  unaffected  tissues,  no 
matter  how  far  it  may  extend,  and  the  subject 
must  be  removed  from  service  or  worked  with 
a  breast  collar.    To  leave  any  part  of  the  dead 
tissue  in  the  cavity  or  to  subject  the  neck  to 
continued  injury  by  working  the  patient  with 
a  collar  will  encourage    the    development    of 
chronic  fistula  and  the  attendant  results.    We 
therefore  advise  that  all  sitfasts  be  managed 
witli  this  end  in  view,  that  the  patient  be  sub- 
mitted to  a  proper  operation  and  the  wound 
treated  as  it  should  be  after  the  operation.  The 
extirpation  of  deep  sitfasts  and  the  application 
of  caustic  into  the  cavity  in  our  hands  have  not 


TREATMENT  103 

been  found  to  be  good  practice.  We  have  de- 
pended upon  the  completeness  of  the  extkpa- 
tion  as  the  main  treatment,  and  in  order  to 
properly  carry  out  this  plan  we  have  found 
it  necessary  to  place  the  patients  in  the  re- 
cumbent position  with  the  neck  well  stretched 
downward  to  expose  the  field  to  the  best  ad- 
v^antage.  Attempts  to  extirpate  sitfasts  of 
this  character  in  the  standing  position  end  in 
failure  to  remove  all  of  the  dead  elements. 
With  the  head  elevated,  the  skin  folded,  the 
patient  lunging  about  and  the  blood  masking 
the  view,  it  is  never  possible  to  work  accu- 
rately, and  a  misdirected  or  incomplete  extir- 
pation is  the  result. 

By  placing  the  patient  on  the  operating  table 
or  down  on  the  ground  with  ropes,  the  neck 
can  be  drawn  downward,  the  parts  cleaned, 
the  blood  well  baled  and  the  whole  mass  of 
dead  and  unviable  tissues  can  be  cut  away. 
Prompt  healing  will  then  follow. 

Once  the  fistula  has  formed  it  will  be  neces- 
sary to  operate  promptly  to  prevent  the  spread 
of  the  advancing  inflammation  into  the  lamel- 
lar portion  of  the  ligament. 

We  cast  the  patient  clean  and  shave  the  neck 
and  then  make  an  incision  no  less  than  eiQ'ht 
inches  long  in  the  median  line  through  the 
skin,  pad  of  the  mane  and  down  between  the 


104  FISTULA  AND  POLL-EVIL 

two  halves  of  the  hgament.  Widening  the 
wound  with  the  tumor  forceps  we  then  resect 
as  much  of  the  ligament  as  is  thought  to  be 
diseased,  making  sure  that  the  lowest  limits  of 
the  disease  have  been  reached.  In  the  average 
case,  not  yet  encroaching  into  the  lamellar  por- 
tion, the  bottom  of  the  cavity  is  found  just 
under  the  funicular  portion  of  the  ligamnt. 
The  woimd  is  treated  without  drainage  by 
smothering  it  well  with  boric  acid  and  iodoform 
until  cicatrization  is  well  advanced. 


POLL-EVIL 

The  Poll 

The  poll  or  nape  of  the  neck  of  quadrupeds 
having  a  long  highly  mobile  neck  and  large 
head  is  an  important  region.  Although  less 
complicated  from  the  anatomical  standpoint 
than  the  withers  it  is  nevertheless  composed  of 
a  great  many  separate  anatomical  structures 
and  although  more  shallow  than  the  withers 
its  relations  to  the  large  nerve  centers  makes 
affections  of  the  poll  more  or  less  dreaded  from 
the  view  point  of  disease  and  of  surgery.  The 
structures  involved  in  poll-evil  are  contiguous 
to  the  coverings  -of  the  spinal  cord  in  the 
atlanto-axoid  space,  to  the  occipito-atlantoid 
articulation  and  finally  to  the  meminges  and 
the  brain.  It  is  plain  that  no  chronic  patholog- 
ical process  so  serious  as  poll-evil  can  so- 
journ unchecked  without  sooner  or  later  im- 
plicating some  of  these  structures  if  not  all  of 
them.  The  surgical  anatomy  of  the  withers 
does  not  include  a  trochoid  articulation  and  its 
relations  to  the  sjiinal  cord  are  more  remote. 

The  surgical  anatomy  of  the  poll  includes, 
the  skin,  the  pad  of  the  mane,  the  atlas,  the 


106  FISTULA  AND  POLL-EVIL 

axis,  the  occipital  crest,  the  occipito-atlantoid 
articulation  the  atlanto-axoid  ligament,  the 
spinal  cord,  the  funicular  portion  of  the  liga- 
mentum  nuchse,  the  musculature,  the  blood  sup- 
ply, the  anterior  end  of  the  sj)inal  cord  the 
meninges,  the  medulla  oblongata,  the  spinal  ac- 
cessory nerve,  and  the  first  two  spinal  nerves. 

The  shin  of  the  central  line  of  the  poll  is 
thick  and  inseparable  from  the  thick  pad  of  the 
mane  lying  immediately  beneath  it.  On  the 
sides  of  the  mane  it  is  thin,  somewhat  delicate 
in  texture,  but  possesses  nothing  out  of  the 
ordinary  to  describe.  On  the  sides,  the  borders 
of  the  wing  of  the  axis  can  be  felt  through  it. 
Elsewhere  the  outlines  of  the  bones  can  be 
palpated  through  it.  In  old  cases  of  poll-evil 
it  is  riddled  with  perforations  and  often  it  con- 
tains scars  of  previous  perforations. 

TJie  pad  of  the  mane  at  the  poll  is  very 
heavy  especially  in  the  draft  breeds  of  horses, 
often  exceeding  two  inches  in  thickness.  In  the 
lighter  breeds  as  for  example  the  thorough- 
breds it  is  thin  and  in  some  subjects  it  does  not 
exist.  The  pad  here  like  that  at  the  base  of 
the  neck  is  composed  of  elastic  tissue  and  fat 
matted  into  a  very  firm  structure  homogeneous 
in  appearance,  and  always  very  vascular. 

The  atlas,  or  first  cervical  vertebra  possesses 


POLL-EVIL  107 

none  of  the  characteristics  of  vertebrae  in  gen- 
eral. It  articulates  by  means  of  diarthrodial 
articulations  with  the  occipital  condyles  an- 
teriorly and  with  the  odontoid  process  of  the 
axis  posteriorly.  Its  wide  expansive  dorsal 
surface  gives  attachment  to  the  muscles  to 
which  it  is  related. 

Its  wings  which  extend  downward  and  out- 
ward become  gradually  thinner  and  thicken 
again  into  a  roughed  heavy  border.  Each  one 
is  perforated  with  a  large  foramen  which  gives 
passage  to  the  occipital  artery,  in  its  course 
from  the  carotid  to  the  region  of  the  poll. 

The  whole  dorsal  face  is  a  smooth  expanse 
interrupted  only  by  a  slight  median  elevation 
representing  the  superior  spinous  process. 

The  dorsal  surface  of  the  atlas  is  important 
in  poll-evil  because  it  sooner  or  later  becomes 
affected  with  periosteitis  and  osteitis  on  ac- 
count of  its  close  relations  to  the  disease  process 
in  and  about  the  ligament um  niich^.  It 
serves  as  a  floor  for  the  abscess  cavity  from 
which  it  is  often  separated  only  by  a  carpet  of 
granulation  tissue  attached  to  the  periosteum. 

The  axis  or  second  cervical  vertebra  may  be 
said  to  be  the  posterior  boundary  of  the  poll- 
evil  process.  It  is  seldom  itself  involved  in 
disease.  Its  crest  or  superior  spinous  process 
stands  above  the  level  of  the  axis  where  it  serves 


108  FISTULA  AND  POLL-EVIL 

as  a  pillar  for  the  ligamentum  nuchas  to  bridge 
over  the  space  between  it  and  the  nuchal  (oc- 
cipital) crest.  The  ligamentum  nuchse  is,  how- 
ever, attached  to  it  only  by  the  lamellar  por- 
tion, which  at  this  point  is  very  thick. 

Tlie  nuchal  {occipital)  crest  is  a  process  of 
the  occipital  bone  extending  upward  to  give 
attachment  to  the  ligamentum  nuchee  and  to 
the  muscles  of  the  poll.  It  has  a  rough  border 
and  a  somewhat  concave  posterior  face  which 
is  depressed  at  one  point  on  each  side  of  the 
median  line  to  receive  each  half  of  the  ligament. 
Its  upper  outlines  determine  the  profile  of  the 
space  between  the  ears. 

The  compact  tissue  of  the  occipital  crest  is 
dense  and  hard  particularly  along  the  summit. 
The  cells  of  the  cancellated  tissue  are  large  and 
the  plates  separating  them  are  thin  and  there- 
fore easily  permeated  with  inflammatory  proc- 
esses. Although  the  occipital  crest  is  not  en- 
croached upon  by  disease  in  poll-evil  itself,  it 
sometimes  becomes  affected  by  a  chronic  os- 
teitis from  chiseling  into  it  to  effect  drainage 
as  recommended  by  Williams. 

The  atlanto-acvoid  ligament  covers  the  gap 
intervening  dorsally  between  the  anterior  por- 
tions of  the  axis  and  the  posterior  part  of  the 
atlas.  This  space  is  about  an  inch  and  a  half 
to  two  inches  long  and  about  an  inch  wide,  be- 


POLL-EVIL  109 

neath  which  hes  the  spinal  cord  unprotected 
by  bony  covering.  Above  the  intervertebral 
ligament  there  is  a  thick  musculature  and  the 
funicular  portion  of  the  ligamentum  nuchse. 

The  occipito-atlantoid  articulation  is  a  diar- 
throsis  whose  large  capsular  ligament  is  ar- 
ranged to  include  both  occipital  condyles.  It 
is  protected  superiorly  by  muscles  which  also 
separate  it  from  the  ligament  laterally. 

The  atlantoid  bursa — the  initial  seat  of  al- 
most all  poll-evils — lies  between  the  ligamen- 
tum nuchge  and  the  dorsal  arch  of  the  atlas. 
This  bursa  has  no  connection  with  the  articu- 
lation. 

The  spinal  cord  is  exposed  in  two  places  to 
both  the  disease  and  the  operation  against  poll- 
evil.  It  is,  however,  in  the  atlanto-axoid  space 
that  it  is  most  likely  to  be  encroached  upon. 
The  musculature  covering  it  in  the  atlanto- 
axoid  space  or  the  intervertebral  ligament,  is 
usually  the  floor  of  the  abscess  cavity  but  some- 
times these  structures  are  degenerated  and  per- 
forated in  a  downward  direction  until  first  the 
meninges  and  later  the  cord  becomes  involved. 
The  cord  exposure  in  the  space  is  about  one 
and  a  half  to  two  inches.  The  cord  must  also 
be  thought  of  when  packing  wound  cavities 
with  hemostatic  packs  because  its  covering  is 
compressible  and  considerable  spinal  pressure 


no  FISTULA  AND  POLL-EVIL 

may  be  caused  by  wadding  the  cavity  too  tight. 

The  other  place  through  which  the  spinal 
cord  becomes  exposed  is  at  the  occipito-atlant- 
oid  articulation.  Here  it  is  attacked  by  en- 
croaching disease  after  the  capsule  of  the  joint 
has  been  invaded. 

The  ligamenUimi  nuchse  is  a  powerful,  elas- 
tic apparatus,  the  principal  function  of  which 
is  to  assist  the  extensor  muscles  of  the  head  and 
neck.  It  extends  from  the  occipital  bone  to 
the  withers,  where  it  is  directly  continuous  with 
the  supraspinous  ligament.  It  consists  of  two 
parts,  funicular  and  lamellar. 

The  funicular  part  arises  from  the  external 
occipital  protuberance  and  the  fossa  below  it 
and  is  inserted  into  the  summits  of  the  verte- 
bral spines  at  the  withers. — Sisson. 

It  is  between  the  funicular  portion  of  this 
ligament  and  the  dorsal  arch  of  the  atlas  that 
the  bursa  (supra-atloid)  lies.  At  the  pole  the 
funicular  part  consists  of  two  bands  closely  at- 
tached to  each  other.  The  lamellar  portion  of 
the  ligamentum  nuchas  is  not  attached  to  the 
atlas,  but  begins  at  the  axis  to  which  a  ver} 
tliick  and  strong  digitation  is  attached. 

Ohliqmis  Cajntis  Antcfior.  This  is  a  short, 
flat  and  nearly  square  muscle,  having  tendin- 
ous intersections.  It  originates  from  the  an- 
terior edge  and,  ventral  siu'face  of  the  wing  of 


POLL-EVIL  111 

the  atlas  inserts  to  the  parmastoid  process 
nuchal  (occipital)  crest  and  the  mastoid  pro- 
cess. 

Obliquus  Capitis  Posterior  (Posticus) .  This 
muscle  lies  upon  the  dorsolateral  aspect  of  the 
atlas  and  axis.  It  is  broad,  flat,  thick  and 
fleshy.  Its  origin  is  from  the  side  of  the  spine 
and  the  posterior  articular  process  of  the  axis. 
It  inserts  to  the  dorsal  surface  of  the  wing  of 
the  atlas.  Its  function  is  chiefly  to  rotate  the 
atlas,  and  by  this  means,  the  head. 

Rectus  Capitis  Dorsalis  Major,  This  mus- 
cle originates  from  the  edge  of  the  spinous 
process  of  the  axis  and  inserts  to  the  occipital 
bone,  below  the  tendon  of  insertion  of  the  com- 
plexus.  It  is  in  contact  with  the  ligamentum 
nuchse. 

Rectus  Capitis  Dorsalis  Minor.  This  is  2 
small  muscle  which  lies  under  the  rectus  cap- 
itis dorsalis  major.  It  originates  from  the 
dorsal  surface  of  the  atlas  and  inserts  to  the 
occipital  bone  beneath  the  point  of  insertion  of 
the  last  named  muscle.  It  is  lateral  to  the 
cordiform  portion  of  the  ligamentum  nuch^. 

Rectus  Capit us  Ventralis  (Auticus)  Major, 
This,  the  long  flexor  muscle  of  the  head  has  its 
origin  posteriorly  from  the  transverse  process- 
es of  the  third,  fourth  and  fifth  cervical  verte- 


112  FISTULA  AND  POLL-EVIL 

brae.  It  inserts  to  tubercles  which  occur  at 
the  junction  of  the  basilar  part  of  the  occipital 
bone  with  the  body  of  the  sphenoid.  These 
muscles  (the  pair)  may  be  said  to  form  a  roof 
for  a  part  of  the  pharynx. 

The  blood  supply  of  the  poll  is  from  three 
sources:  The  occipital,  the  superior  cervical 
and  the  vertebral  arteries.  The  first  named 
is,  however,  the  chief  one.  It  is  a  radical  of 
the  carotid  and  passes  to  the  region  of  the  poll 
through  the  large  foramen  in  the  wing  of  the 
atlas.  Its  branches  anastomose  with  the  other 
two.  The  branches  are  numerous  and  often 
through  the  influence  of  the  disease  become 
greatly  enlarged.  In  the  operation  for  poll- 
evil  the  incision  being  a  standard  one,  made 
irrespective  of  blood  vessels,  there  is  nothing  of 
importance  to  say  about  avoiding  them,  ex- 
cept that  lateral  invasion  into  the  region  of  the 
alar  foramen  through  which  the  occipital  passes 
must  be  made  cautiously.  In  short,  no  especial 
effort  except  this  one,  is  ever  made  to  avoid 
arteries. 

The  7ierve  supply  is  of  no  especial  impor- 
tance. It  is  derived  from  the  spinal  accessory 
and  the  first  two  spinal  nerves,  none  of  which 
is  ever  seen  in  the  operation,  nor  is  a  solution 
on  the  continuity  of  their  branches  attended 
with  anv  observable  harm. 


PATHOGENESIS 

Poll-evil,  like  fistula  of  the  withers,  we  di- 
vide into  two  classes :  typical  and  atypical.  By 
typical  poll-evil  we  mean  those  cases  that  de- 
velop independent  of  any  known  cause  in  the 
atlantoid  bursa,  just  as  fistula  of  the  withers  so 
frequently  develops  in  the  dorsal  bursa.  By 
atypical  poll-evil — a  rare  entity — we  designate 
those  that  originate  from  abrasions  or  wounds. 
The  former  invade  outward  while  the  latter  in- 
vade inward  from  the  initial  seat. 

The  course  of  all  typical  poll-evil  we  divide 
into  three  stages :  the  saccular  stage,  the  phleg- 
monous stage  and  the  fistulous  stage,  as  in  fis- 
tula of  the  withers. 

The  saccular  stage  begins  in  the  form  of  a 
distension  of  the  atlantoid  bursa  with  a  sero- 
fibrinous fluid  that  is  sterile  and  whose  influ- 
ence causes  the  formation  of  a  well  defined 
membranous  wall  composed  of  a  cellular  inter- 
nal face  fortified  by  fibrous  tissue.  As  the  les- 
ion becomes  older  the  fibrous  tissue  becomes 
more  abundant,  sometimes  amounting  to  an 
extensive  fibrosis  of  the  surrounding  muscula- 
ture. The  sac  may  bulge  on  one  or  both  sides 
and  may  be  small  or  large  enough  to  conspicu- 


114  FISTULA  AND  POLL-EVIL 

ously  deform  the  region.  Being  imbedded  un- 
der firm  tissues,  it  is  often  hard  to  the  touch, 
fluctuating  only  after  pushing  its  way  to  the 
surface  on  the  side  of  the  hgamentum  nuchge 
and  pad  of  the  mane.  Evacuating  the  contents 
of  the  sac  during  this  stage  yields  an  amber 
colored  fluid  carrying  coagulated  detritus  con- 
taining no  bacteria. 

This  sac  may  sojourn  indefinitely  and  may 
even  for  a  time  seem  to  disappear  entirely,  only 
to  reappear  subsequently. 

Evacuation  and  careful  attention  to  the 
tract  and  cavity  may  sometimes  end  the  pro- 
cess by  slow  cicatrization.  Thus  sometimes  a 
poll-evil  is  cured  without  a  radical  operation. 
In  most  cases,  however,  the  invasion  of  the 
tract  and  cavity  with  extraneous  microbes 
ends  in  chronic  fistula. 

The  plilegmonous  stage.  In  the  usual  course 
of  events  the  saccular  stage  ends  in  infection  of 
the  cavity.  The  manner  in  which  microorgan- 
ism gains  access  to  the  cavity  is  not  known, 
but  the  frequency  with  which  poll-evil  is  asso- 
ciated with  strangles  and  influenza  has  led  us 
to  believe  that  these  diseases  play  an  important 
role  in  its  etiology ;  the  affected  atlantoid  bursa 
serving  as  a  focus  of  localization  for  microor- 
ganisms contained  in  the  blood  after  these  dis- 
eases. 


PATHOGENESIS  115 

During  this  stage  the  patient  becomes  sick 
and  severeh^  hindered  in  the  movements  of  the 
head.  It  becomes  manifestly  opisthotonic  in 
attitude,  and  develops  a  body  temperature  of 
from  two  to  three  degrees  above  normal.  The 
poll  becomes  progressively  more  painful  to  the 
touch  and  the  sides  of  the  neck  are  streaked 
with  radiating  lines. 

The  Fistulous  Stage 

Either  by  lancing  or  by  spontaneous  ripping 
and  bursting  of  the  abscess  this  stage  sooner  or 
later  passes  into  the  stage  of  chronic  discharge 
— fistula.  If  the  infection  is  not  a  virulent  one 
the  development  is  very  slow — cold  abscess — 
and  fibrosis  becomes  a  prominent  feature  of  the 
process.  That  is  to  say,  if  the  accumulating 
pus  is  not  released  the  process  reacts  upon  the 
surroundings  in  some  way  that  causes  the  mus- 
cular elements  to  become  fibrous. 

The  fistulous  and  the  phelgmonous  stages 
are  of  course  influenced  by  microorganism. 
These  exert  a  more  or  less  destructive  influence 
upon  the  ligamentum  nuch«,  which  is  in  the 
center  of  the  theater  of  attack.  Once  this  fibro- 
elastic  structure  has  been  damaged  it  acts  as 
the  underlying  cause  of  subsequent  pathologic 
processes.  Riddled  with  perforations,  shred- 
ded with  bundles  of  its  fibers  which  remain 


116  FISTULA  AND  POLL-EVIL 

stubbornly  attached,  and  carpeted  here  and 
there  with  dormant  granulations  it  prevents 
cicatrization  of  the  abscess  cavity.  It  is  this 
stubborn  viability  of  the  ligamentum  nuchse 
that  is  responsible  for  the  chronicity  of  poll- 
evil. 

This  stage,  like  that  of  fistula  of  the  with- 
ers, continues  indefinitely,  healing  at  one  place 
and  bursting  at  another  and  all  of  the  while 
transforming  the  muscles  into  fibrous  tissue. 
The  inflammatory  process  extends  into  the  per- 
iosteum of  the  atlas,  into  the  capsule  of  the  oc- 
cipito-atlantoid  articulation,  into  the  meninges 
and  brain,  into  the  neural  canal  and  into  the 
spinal  cord,  producing  the  variety  of  comph- 
cations  for  which  poll-evil  is  known. 

An  old  poll-evil  left  to  sojourn  unmolested 
or  one  indifferently  treated  usually  exhibits 
the  following  morbid  states:  a  tumefied  poll, 
one  or  more  apertures  discharging  pus,  scars 
of  previous  apertures,  encrustations  of  dried 
pus  matted  into  the  mane  and  surrounding 
hairs,  extended  head  from  fibrous  anchylosis 
of  the  occipito-atlantoid  articulation  and  a  wab- 
bly gait  that  becomes  more  and  more  accentu- 
ated until  the  patient  is  unable  to  rise.  Sec- 
tioned, the  poll  is  foimd  to  have  been  trans- 
formed into  a  mass  of  hard,  fibrous  tissue, 
which  fuses  all  of  the  component  structures  in- 


PATHOGENESIS  117 

to  one  homogenous  mass.  This  mass  is  riddled 
with  tracts  and  under  the  now  unrecognizable 
hgamentum  nucha  is  an  abscess  cavity  almost 
closed  by  granulation  tissue.  The  surface  of 
the  atlas  is  rough  from  destruction  of  its  peri- 
osteum and  it  may  be  studded  by  numerous 
vegetations  of  bony  growths.  There  is  found 
sometimes  a  shredded  condition  of  parts  of  the 
ligament,  parts  that  have  partly  loosened  from 
necrosis.  In  some  cases,  usually  in  aged  horses, 
the  hgament  is  permeated  with  calcareous  de- 
posits, each  of  which  is  well  incarcerated  with 
connective  tissue  elements. 

Atypical  Poll-Evil 

The  atypical  poll-evil  begins  with  a  halter 
abrasion  of  some  kind  of  wound  that 
gives  admission  to  pyogenic  microorganisms. 
It  is  at  first  a  subcutaneous  abscess, 
and  if  carbuncular  in  character  may  give 
rise  to  all  of  the  symptoms  of  a  typical 
poll-evil  in  the  phlegmonous  stage.  This 
form  will  differ  from  the  typical  form  in 
that  cicatrization  will  follow  evacuation  of  its 
pus  and  general  slough.  If  deep  and  the 
slough  should  be  attached  to  the  ligamentum 
nuch^e  a  chronic  poll-evil  having  all  of  the  char- 
acteristics of  the  other,  the  typical  kind,  will 
supervene.     In  this  case  the  ligament  is  at- 


118  FISTULA  AND  POLL-EVIL 

tacked  from  without.  Its  dorsal  face  is  at- 
tack first,  while  in  the  other,  the  under  part 
at  the  atlantal  bursa,  is  attacked  before  the 
upper  part  becomes  involved. 

This  form  of  fistula  can  only  be  recognized 
as  such  at  the  early  stage,  for  once  spread 
deeply  into  the  poll  it  has  no  differentiating 
qualities. 

Etiology 

The  cause  of  poll-evil,  like  that  of  fistula  of 
the  withers,  is  by  no  means  settled.  The  aca- 
demic explanation  (traumatism)  that  seems  to 
have  satisfied  all  past  writers  on  the  subject 
entirely  lacks  confirmation.  Wherever  this 
subject  is  discussed  verbally  or  in  literature  the 
matter  of  etiology  is  always  indifferently 
passed  over  as  if  it  is  a  settled  fact  that  poll- 
evil  is  a  traumatism.  No  one  seems  to  have 
ever  questioned  seriously  the  theory  of  trau- 
matic origin  in  spite  of  the  fact  that  no  one 
seems  to  have  ever  actually  traced  a  typical 
poll-evil  to  any  definite  traumatism.  The 
truth  seems  to  be  that  traumatism  plays  no 
part  whatever  in  its  cause.  Except  in  the  rare 
case  that  originates  with  a  wound  of  the  poll 
it  is  plain  that  we  must  seek  farther  for  a  rea- 
sonable theory  of  cause.  It  is  our  opinion  that 
the  cause  is  unknown,  that  the  serous  sac  that 
starts  it  develops  under  influences  we  cannot 


PATHOGENESIS  119 

explain  at  the  present  time.  We  believe,  how- 
ever, that  infectious  diseases  such  as  influenza 
or  strangles  play  an  important  role  in  the 
course  if  not  also  in  the  original  cause.  Where 
influenza  is  rampant  so  will  poll-evil  and  fis- 
tula of  the  withers  be  found  rampant.  We  are, 
however,  not  today  justified  as  laying  this 
down  as  an  absolute  law,  as  subsequent  inves- 
tigations no  doubt  may  show  that  its  cause 
is  more  specific. 


SYMPTOMS 

Typical  poll-evil  is  first  seen  as  a  slight  bulg- 
ing of  one  or  both  sides  of  the  poll.  There  are 
at  first  no  manifestations  of  pain  either  on  pal- 
pation or  in  movements  of  the  head.  Later  as 
the  phlegmonous  stage  begins  the  movements 
of  the  head  become  painful  and  palpations  an- 
noy the  patient.  Some  will  oppose  any  at- 
tempt to  touch  the  region.  Before  the  abscess 
points  there  are  radiating  lines  along  the  sides 
of  the  neck.  The  head  is  held  extended,  later- 
al movements  are  painful  and  the  whole  body 
is  turned  stiffly,  as  if  tlie  whole  axial  skeleton 
were  anchylosed. 

Later  the  abscess  points  and  discharges  its 
contents  over  the  sides  of  the  neck.  The  aper- 
ture may  then  discharge  a  limited  quantity  of 
pus  for  weeks  that  keeps  the  region  continual- 
ly soiled  and  irritated.  The  aperture  will  fin- 
ally close  gradually  as  the  discharges  become 
less  abundant,  but  this  will  eventually  be  fol- 
lowed by  the  forming  of  another  abscess,  which 
will  behave  in  the  same  manner  as  the  preced- 
ing one,  and  so  the  condition  proceeds.  While 
these  abscesses  and  tracts  are  forming,  the  mus- 
culatm'e  involved  becomes  considerably  elevat- 


122  FISTULA  AND  POLL-EVIL 

ed  above  the  surrounding  level.  The  head,  at 
first  extended  from  the  pain  of  the  forming  ab- 
scesses, gradually  becomes  fixed  in  the  extend- 
ed position  from  fibrous  anchylosis  of  the  re- 
gion. An  animal  affected  with  poll-evil  has  a 
characteristic  attitude  simulating  the  opisthot- 
onos of  tetanus. 

Poll-evil  that  becomes  infected  before  there 
is  an}^  enlargement  of  the  region  must  be  diag- 
nosed sometimes  entirely  from  this  attitude 
and  from  the  pain  produced  by  manipulating 
the  head. 

Rare  cases  cause  epiliptiform  seizures  when 
the  head  is  moved  about  manually  or  in  work- 
ing. In  such  instances  when  local  evidence  is 
entirely  lacking  because  of  the  depth  of  the 
infected  focus  it  may  not  be  an  easy  matter  to 
arrive  at  a  diagnosis. 

The  development  of  poll-evil  is  always  grad- 
ual, although  it  may  often  assume  considerable 
projDortions  before  attracting  attention.  The 
mane  and  forelock  shelter  the  region  so  effec- 
tually in  some  animals  that  the  enlargement 
develops  unnoticed  until  discharges  appear. 
These  cases  are,  however,  rare,  as  the  pain  and 
the  position  of  the  head  which  precede  the  dis- 
charge are  usually  pronounced  enough  to  at- 
tract attention. 

The  average  poll-evil  when  submitted  to  the 


SYMPTOMS  123 

veterinarian  is  either  found  as  an  enlargement 
on  one  or  both  sides  of  the  poll  or  else  as  a  sup- 
purative condition  that  matts  the  hairs  of  the 
mane  and  soils  the  region  with  dried  pus. 

As  the  disease  progresses  the  patient  be- 
comes distinctly  unthrifty  in  appearance  and 
loses  flesh.  Locomotion  is  slow.  The  patient 
gropes  about  and  trots  only  w^hen  urged.  Feed- 
ing from  the  bottom  of  the  manger  and  grazing 
is  painful. 

Later,  as  nervous  complications  develop,  the 
hind  quarters  wabble  inordinately  and  rising 
becomes  more  and  more  difficult.  Finally  the 
failing  subject,  unable  to  stand,  dies  from  de- 
cubital complications,  if  it  is  not  sooner  killed 
to  end  its  misery. 

Complications 

Paralysis. — The  most  serious  complication 
is  paralysis  due  to  advancement  of  the  inflam- 
matory process  into  the  meninges,  the  cord  and 
even  the  brain  itself.  The  invasion  is  usually 
at  the  atlanto-axoid  space,  but  sometimes  oc- 
curs through  the  occipito-atlantoid  articulation. 
When  these  nervous  structures  become  in- 
volved early  in  the  progress  of  the  disease,  the 
case  is  not  necessarily  a  hopeless  one  because 
of  the  nerve  involvement,  since  an  operation 
which  evacuates  the  pus  externally  may  turn 


124  FISTULA  AND  POLL-EVIL 

the  tide  of  the  inflammatory  process  towards 
resolution.  On  the  other  hand,  if  nervous  com- 
plications develop  as  a  phase  of  later  stages, 
the  case  is  always  hopeless.  The  practitioner 
is  warned  against  operating  upon  such  cases, 
because  the  operation  is  always  blamed  for  the 
unfavorable  termination,  and  in  fact  rightly 
so,  since  the  advancement  of  the  process  into 
the  cord  and  brain  is  accentuated  rather  than 
retarded  by  surgical  treatment  at  this  stage  of 
the  development.  And  besides,  patients  thus 
stricken  are  unable  to  withstand  the  enfeebling 
influence  of  such  a  major  operation. 

Involvement  of  the  Occipito-Atlantoid  Ar- 
ticulation.— Lying  adjacent  to  the  initial  focus 
of  the  disease,  this  joint  very  often  becomes 
infected  within  its  capsular  ligament  at  an 
early  stage.  As  a  rule,  however,  this  compli- 
cation features  later  stages,  the  joint  becoming 
involved  gradually  through  the  medium  of  the 
atlas.  The  periosteum  and  then  the  bone, 
soaked  with  pus  develop  chronic  inflammation 
that  advances  into  the  joint  through  the  articu- 
lar cartilage.  When  this  occurs  it  is  only  a 
matter  of  weeks  before  serious  results  ensue 
through  involvement  of  the  meninges.  The 
subject  thus  affected  is  in  sore  straits  from  the 
severe  pain  it  suffers,  especially  in  moving  the 
head. 


SYMPTOMS  125 

This  complication  is  one  of  the  common 
causes  of  recurrences  and  failures  of  operative 
treatment.  It  is  incurable  and  if  known  to 
exist  should  be  regarded  as  a  contra-indication 
of  the  radical  operation  now  universally  recom- 
mended for  poll-evil. 

Secondary  Abscesses. — Although  there  are 
fewer  recesses  and  lamellar  spaces  for  pus  to 
burrow  into  about  the  poll  than  there  are  about 
the  withers,  there  are,  nevertheless,  places 
where  pus  will  escape  from  the  immediate  re- 
gion of  the  seat  of  poll-evil  and  cause  secondary 
abscesses.  The  common  one  that  occurs  both 
before  and  after  operating,  localized  at  some 
point  of  the  neck  along  the  ligamentum  nuchge. 
We  have  observed  cases  in  which  tracts  extend- 
ed down  the  ligament  as  far  as  the  base  of  the 
neck,  the  route  followed  being  the  space  be- 
tween the  cervical  muscles  and  the  lamellar 
portion  of  the  ligaments  just  under  the  fu- 
nicular portion.  Most  of  these  abscesses,  how- 
ever, localize  at  the  level  of  the  axis,  where  they 
sometimes  produce  a  stubborn  condition  to 
handle  by  implicating  the  lamellar  portion  of 
the  ligament  at  that  point. 

Another  focus  of  abscess  formation  is  the 
space  between  the  anterior  part  of  the  v»ing 
of  the  atlas  and  the  styloid  process  of  the  oc- 
cipital.    This  complication  is  disclosed  at  the 


126  FISTULA  AND  POLL-EVIL 

time  of  the  operation.  After  the  ligament  has 
been  removed,  a  sound  can  sometimes  be  passed 
downward  five  or  six  inches  before  it  touches 
the  bottom  of  the  cavity. 

Chronic  Septicemia  co-exists  to  a  certain  ex- 
tent in  all  bad  cases  of  poll-evil.  It  is,  however, 
less  serious  than  in  fistula  of  the  withers,  since 
the  region  is  smaller. 


TREATMENT 

Xo  time  should  be  lost  in  submitting  a  poll- 
evil  to  radical  treatment.  The  new  case 
should  be  lanced  and  the  cavities  irrigated 
with  antiseptics  for  a  week  or  ten  days  and 
then  promptly  operated  upon.  There  will  be 
nothing  gained  by  waiting  longer,  as  the  old- 
er the  case  the  more  it  will  have  damaged  the 
structures  of  the  region  and  thus  the  more  diffi- 
cult it  will  be  to  cure.  In  cases  found  in  the 
phlegmonous  stage  and  before  the  abscess  has 
burst  we  also  recommend  lancing  and  irriga- 
tions as  preparatory  treatment. 

Subjects  having  unmistakable  involvement 
of  the  occipito-atlantoid  articulation  and  all 
those  already  showing  nervous  complications 
should  be  left  severely  alone  and  pronounced 
incurable.  Weak  subjects  that  do  not  exhibit 
sufficient  strength  to  withstand  a  major  opera- 
tion should  likewise  be  left  alone.  These  might, 
however,  be  submitted  to  a  restorative  treat- 
ment until  it  is  thought  advisable  to  interfere 
fiu-ther. 

The  Radical  Operation  for  Poll-Evil 

Restraint. — Xo  attempt  should  ever  be  made 
to  operate  in  the  standing  position,  no  matter 


128  FISTULA  AND  POLL-EVIL 

how  tractable  the  patient  may  seem.  Opera- 
tions performed  in  the  standing  position  under 
some  form  of  narcosis  always  turn  out  to  be 
very  unsurgical  exhibitions.  The  patient  should 
be  cast  with  ropes  or  else  placed  upon  an  op- 
erating table.  The  latter  is  much  the  best  be- 
cause of  the  elevated  position  of  the  head.  On 
the  floor  or  ground  the  field  is  not  so  accessible 
and  must  be  elevated  by  blocking  the  neck  and 
head  up  in  some  way  to  bring  it  where  the  sur- 
geon can  work.  Chloroformed,  the  patient  can 
be  handled  better  than  under  narcosis.  When 
rope  restraint  is  used  chloroform  should  really 
be  administered  because  it  is  difficult  to  control 
the  sweeping  movements  of  the  head  of  a  par- 
tially anesthetized  subject  down  on  the  ground. 
Our  plan  in  field  work  is  to  clean  up  the  poll 
well  while  the  subject  is  standing,  cast  with 
ropes,  administer  chloroform  and  then  block 
up  the  neck  and  poll  with  a  tightly  filled  sac  of 
straw.  This  sac  may  be  bound  to  the  neck  and 
head  with  cords,  one  around  the  middle  of  the 
cervical  region  and  one  around  the  head  just 
below  the  eyes.  Thus  tied  the  blocking  will 
stay  in  place  when  the  neck  and  head  move. 
This  form  of  blocking  is  particularly  essential 
when  the  operation  is  done  on  the  ground  un- 
der narcosis.  It  is  important  that  the  sac  be 
well  filled,  otherwise  it  will  flatten  down  and  do 


TREATMENT  12^ 

no  good.  For  this  purpose  we  also  use  when 
available  two  or  three  buggy  or  automobile  seat 
cushions. 

The  head  should  be  maintained  at  about  its 
normal  angle  with  the  neck.  Extreme  ex- 
tension or  flexion  is  undesirable. 

The  patient  should  lie  on  its  right  side.  Al- 
though this  is  not  mandatory,  the  surgeon  finds 
that  it  is  easier  to  cut  backward  with  the  right 
hand  when  the  patient  is  thus  positioned. 

Incision.  First  Step. — The  scalpel  is  pushed 
carefully  downward,  with  its  cutting  surface 
backward,  just  behind  the  occipital  crest  in 
the  very  middle  of  the  neck,  until  it  either  en- 
ters the  bursa  or  is  blocked  by  the  occipital 
bone.  Its  blade  should  be  buried  about  four 
inches  in  the  average  case.  It  is  then  drawn 
backward,  maintaining  this  depth,  about  eight 
inches.  If  a  longer  incision  is  decided  upon  it 
is  best  to  make  it  more  shallow  posteriorly  be- 
cause of  the  danger  of  invading  the  neural 
canal.  If  a  short  bladed  scalpel  is  used  several 
strokes  will  be  required.  Blood  will  flow  cop- 
iously from  many  sources,  but  no  attempt  is 
made  to  control  it  either  by  ligation  or  forceps. 
It  is  our  experience  that  more  blood  is  lost 
when  the  operation  is  stopped  to  make  these 
attempts  at  hemostasia.     We,  however,  grasp 


130 


FISTULA  AND  POLL-EVIL 


each  edge  of  the  wound  with  a  tumor  forceps 
give  one  to  the  assistant  and  hold  the  other  in 
the  left  hand.    By  drawing  hard  on  these  the 


Fig.  13. — Poll  Evil  Showinc  I^eformity  Due  to  the 
Treatment  With  Caustics. 


bleeding    will    he   controlled   to    some    extent. 

Separating  the  ligament  from  the  occipital 

Crest.    Second  Step, — This  to  us  is  the  most 


TREATMENT  131 

important  part  of  the  operation,  as  it  supplies 
the  first  "landmark"  for  the  subsequent  resec- 
tion.   Those  who  ignore  this  step  will  find  it 


Fig.   14. —  A    Recl'rf^ext  Cask  After  Temporizing  Treatment, 
Note  the  scars   from  lateral  incisions  through  which  drain- 
age had  1)een  attempted. 

difficult  to  locate  the  ligament  and  will  often 
abandon  the  work  without  having  accomplished 


132  FISTULA  AND  POLL-EVIL 

the  main  object — the  resection  of  the  hgament. 

In  this  step  we  lay  the  scalpel  aside  and  take 
up  the  probe-pointed  bistoury.  We  first  pass 
the  index  finger  of  the  right  hand  under  the 
hgament  right  at  the  crest  and  using  the  finger 
as  a  guide  pass  the  bistoury  under  it,  cutting- 
outward  and  upward.  The  ligament  through 
its  extreme  elasticity  will  contract  backwards 
as  fast  as  it  is  cut  and  tlius  reveal  itself  to  the 
operator.  That  is,  the  end  will  come  right  out 
into  the  foreground  after  contracting  back- 
ward an  inch  or  more.  We  then  grasp  the  end 
with  a  tumor  forcep  and  dissect  it  in  the  back- 
ward direction  as  it  is  drawn  upon  with  the  for- 
cep. Over  the  region  most  badly  damaged  by 
disease  it  will  be  found  so  fused  with  the  other 
connective  elements  that  it  can  not  be  said  to 
be  a  distinct  structure.  We  attempt  to  take 
away  as  much  of  this  connective  tissue  as  is 
thought  prudent  as  the  dissection  proceeds 
backward.  The  dissection  is  continued  along 
the  whole  length  of  the  incision  or  until  the 
sound  part  of  the  ligament  is  reached  posteri- 
orly. We  know  when  the  sound  part  is  reached 
by  its  elasticity.  When  the  section  now  held  in 
the  forcep  is  drawn  back  and  forth  the  liga- 
ment it  seen  to  stretch  easily.  Here  it  is  cut 
off. 

The  attention  is  now  directed  to  the  other 


TREATMENT 


133 


side,  as  this  removes  only  one-half  of  the  liga- 
ment. The  operation  must  be  repeated  in  the 
same  way  on  the  opposite  side.  Allowance 
must  be  made  for  a  possible  sectioning  of  the 
ligament  into  two  unequal  parts  when  the  first 


k 

Fig.  15. — The  Operation  Completed. 
Note  that  the  operative  wound  is  packed  so  tightly  that  the 
poll  appears  swollen  even  more  than  before  the  operation. 
Note  also  the  enlargement  of  the  lymphatics  of  the  neck,  due 
to  the  absorption  of  toxic  materials  from  the  suppurating 
area. 


incision  was  made.  That  is  to  say,  when  the 
scalpel  was  drawn  backward  in  making  the  in- 
cision it  may  not  have  traveled  exactly  be- 
tween the  two  lateral  halves  of  the  ligament 
and  thus  has  left  more  to  be  removed  from 


134  FISTULA  AND  POLL-EVIL 

one  side  than  from  the  other.  Sometimes  in 
misdirected  plunges  of  the  scalpel  into  the  poll 
the  ligament  may  all  be  left  on  one  side,  some- 
times two-thirds  is  on  one  side  and  one-third 
on  the  other,  etc.  And  again,  if  the  incision 
was  not  made  straight  there  may  be  more  liga- 
ment anteriorly  than  posteriorly  on  a  given 
side.  These  are  points  to  keep  in  mind  at  all 
times.  The  point  is  to  remove  all  of  it  along 
the  affected  zone,  but  no  more  than  is  necessary 
posteriorly. 

Packing  and  Suturing.  Third  Step. — The 
w^ound  is  now  wadded  with  a  hemostatic  pack 
of  oakum  and  sutured  securely.  We  make  no 
attempt  to  wad  the  cavity  so  very  tight  posteri- 
orly on  account  of  the  danger  of  spinal  pres- 
sure, although  it  must  be  well  filled.  The  ob- 
ject in  making  a  safe  hemostatic  pack  for  poll- 
evil  is  to  distribute  the  pressure  evenly  over 
the  whole  cavity.  That  is,  severe  pressure  from 
hard  lumps  of  the  oakum  must  be  avoided,  es- 
pecially at  the  posterior  end  of  the  wound. 
iWhen  the  patient  is  standing  again  the  poll 
and  bloody  neck  are  washed  off  with  liberal 
ablutions  of  water  and  then  the  poll  is  covered 
w^ith  a  layer  of  oakum  or  cotton  soaked  in  mer- 
curic chlorid  solution  and  this  is  held  in  place 
Avith  a  hood  made  from  muslin  or  common  bur- 
lap. 


TREATMENT  135 

After-care. — At  the  end  of  twenty-four 
hours  the  sutures  are  removed  and  the  packing 
carefully  lifted  out.  Harsh  handling  will  cause 
bleeding  and  should  be  avoided  at  this  early 
moment  after  the  operation.  We  simply  fill 
the  cavity  with  a  cotton  wadding  dripping  with 
mercuric  chlorid  solution  and  replace  the  hood 
for  another  twenty- four  hours  before  attempt- 
ing any  systemic  after-treatment. 

The  subsequent  after-care  consists  of  smoth- 
ering the  w^ound  secretions  by  the  application 
of  abundance  of  boric  acid  and  iodoform  in  the 
proportion  of  95  to  5.  This  should  be  applied 
three  times  a  day  for  the  first  five  days  and 
later  twice  and  still  later  once  a  day. 

Healing  is  usually  complete  in  forty  days. 

Accidents  and  Sequelae 

Hemorrhage  is  a  common  enough  accident 
of  poll-evil.  Always  copious,  it  assumes  seri- 
ous proportions  when  the  operation  is  in  any 
way  delayed.  When  the  anesthesia  or  the 
restraint  miscarries  serious  blood  losses  always 
occur.  Secondary  hemorrhage  is  rare  except 
when  the  cavity  is  too  hashly  handled  when 
the  packing  is  first  removed. 

The  hemostasia  of  poll-evil  operations  lies 
in: 

1.     Stretching    the    wound    apart    forcibly 


136  FISTULA  AND  POLL-EVIL 

with  the  tumor  forcep  as  soon  as  the  incision 
is  made. 

2.  Performing  the  operation  without  delay. 

3.  Packing  the  wound  with  an  even  pres- 
sure with  oakum  securely  retained  with  su- 
tures. 

4.  Avoiding  harsh  handling  until  at  least 
forty-eight  hours  have  elapsed. 

Paralijsis. — We  have  had  animals  become 
entirely  paralyzed  after  poll-evil  operations, 
due  to  having  attempted  to  cure  incurable 
cases  already  having  nervous  complications, 
but  aside  from  those  it  is  always  possible,  when 
due  care  is  not  taken  to  properly  attend  to  such 
a  large  wound  adjacent  to  the  neural  canal, 
for  the  inflammatory  process  to  invade  through 
the  muscles  covering  the  atlanto-axoid  space 
and  produce  trouble  that  did  not  previously 
exist.  Then  again,  undue  pressure  of  a  lumpy 
hemostatic  pack  is  always  a  hazard.  By  avoid- 
ing operations  on  subjects  exhibiting  a  wabbly 
gait,  carefully  packing  the  wound  and  then 
properly  caring  for  it  afterward  there  is  little 
danger  from  this  complication. 

Slough  of  the  Distal  Stump  of  the  Liga- 
ment Nuchae, — Failure  of  the  wound  to  heal 
at  the  posterior  commissure  is  due  always  to 
a  slough  of  the  stump  of  the  ligament.  Some- 
times the  slough  is  small  and  at  other  times  it 


TREATMENT  137 

is  large.  This  sequel  is  manifested  in  two 
ways.  In  some  cases  the  wound  heals  every- 
where except  at  the  posterior  end,  where  a 
small  fistulous  tract  remains.  Probed  it  is 
found  to  be  deep.  If  forceps  are  introduced 
the  slough  can  usually  be  taken  hold  of  and 
drawn  out.  Sometimes  the  aperture  must  first 
be  enlarged. 

The  other  manifestation  is  the  appearance 
of  a  new  phlegmonous  condition  on  each  side 
of  the  neck  just  behind  and  below  the  posterior 
end  of  the  wound.  The  abcess  is  sometimes 
threatening  and  unless  properly  handled  may 
end  in  a  new  fistulous  condition  quite  difficult 
to  handle.  The  first  sign  of  such  a  complica- 
tion, w^hich  usually  occurs  at  about  thirty-five 
to  forty  days  after  the  operation,  must  be  met 
by  making  an  incision  at  the  posterior  end  of 
the  old  wound  downward  into  the  abcess  cav- 
ity, where  a  slough  of  the  stump  of  the  liga- 
ment is  always  awaiting  removal. 

It  is  our  practice  to  make  a  careful  examina- 
tion of  the  wound  at  the  end  of  thirty  days 
with  a  view  of  determining  whether  or  not  such 
a  slough  exists,  and  to  remove  it  if  found. 

Recurrences  and  Failures 

The  failures  from  the  radical  operation  for 
poll-evil  are  almost  always  due  to  procrastina- 


138  FISTULA  AND  POLL-EVIL 

tion.  The  disease  being  left  to  effect  incurable 
damage  to  the  bones,  particularly  to  the  occipi- 
to-atloid  articulation,  can  not  be  cured  entirely 
by  simply  resecting  the  ligament.  Wh^re  the 
ligament  is  removed  early  failures  are  negligi- 
ble. Recurrences  are  due  to  sloughs  of  the  diis- 
tal  stump  referred  to  above  or  to  failure  to 
remove  all  of  the  ligament. 

By  avoiding  old  incurable  cases,  by  resorting 
to  effectual  restraint  and  anesthesia,  by  op- 
erating deliberately  and  without  delay,  by  at- 
tending skillfully  to  the  wound  and  by  keeping 
in  mind  the  slough  of  the  distal  stump,  the  iro- 
ical  operation  for  poll-evil  is  attended  '*'/h  i 
few  failures.  It  should  be  a  routine  measi  .f; 
with  every  veterinary  practitioner. 

And  what  is  writ  is  writ; 

Would  that  it  were  worthier. — Homer. 

THE  END 


Webster  Family  Library  ol  Veterinary  IVIedicine 
Cummings  School  of  Veterinaiy  Medicine  at 
Tufts  University 

Or{f\  \A/pcthnm  RnaH 


